【性能优化】 之 并行执行
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【性能优化】 之 并行执行
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1.給出一個2表關聯的并行查詢執行計劃，并畫出并行數據流圖。<br>
2.就自己本機的硬件情況，通過SQL示例，來找到最優的并行度。<br>
3.針對PARALLEL_DEGREE_POLICY的三個值，分別演示它們的效果。<br>
4.用一個并行的SQL示例，比較10391事件和 V$PQ_TQSTAT結果的異同。<br>
5.分別演示一個DDL和DML操作的并行執行示例。<br>
===============================================================
1.給出一個2表關聯的并行查詢執行計劃，并畫出并行數據流圖。<br>
答：
SQL> set linesize 8000;
SQL> set autotrace traceonly;
SQL> select /*+ PARALLEL(d 2) PARALLEL(e 2) */ d.dname,e.* from scott.dept d inner join scott.emp e on d.deptno=e.deptno;
14 rows selected.
Execution Plan
----------------------------------------------------------
Plan hash value: 197865614
-----------------------------------------------------------------------------------------------------------------
| Id? | Operation?????????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
-----------------------------------------------------------------------------------------------------------------
|?? 0 | SELECT STATEMENT??????? |????????? |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |??????? |????? |??? |
|?? 1 |? PX COORDINATOR???????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |??? |
|?? 2 |?? PX SEND QC (RANDOM)?? | :TQ10001 |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |? Q1,01 | P->S | QC (RAND)? |
|*? 3 |??? HASH JOIN??????????? |????????? |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |? Q1,01 | PCWP |??? |
|?? 4 |???? PX RECEIVE????????? |????????? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWP |??? |
|?? 5 |????? PX SEND BROADCAST? | :TQ10000 |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | P->P | BROADCAST? |
|?? 6 |?????? PX BLOCK ITERATOR |????????? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | PCWC |??? |
|?? 7 |??????? TABLE ACCESS FULL| DEPT???? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | PCWP |??? |
|?? 8 |???? PX BLOCK ITERATOR?? |????????? |??? 14 |?? 532 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWC |??? |
|?? 9 |????? TABLE ACCESS FULL? | EMP????? |??? 14 |?? 532 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWP |??? |
-----------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
?? 3 - access("D"."DEPTNO"="E"."DEPTNO")
Statistics
----------------------------------------------------------
??????? 176? recursive calls
????????? 2? db block gets
??????? 116? consistent gets
???????? 10? physical reads
????????? 0? redo size
?????? 1758? bytes sent via SQL*Net to client
??????? 524? bytes received via SQL*Net from client
????????? 2? SQL*Net roundtrips to/from client
???????? 16? sorts (memory)
????????? 0? sorts (disk)
???????? 14? rows processed
（并行數據流示意圖請看附件）
-----------------------------------------------------------------------
2.就自己本機的硬件情況，通過SQL示例，來找到最優的并行度。<br>
?? ?使用了公司內部的測試服務器，性能上用來做一般的測試服務器應該還算可以：
?? ?配置：
?? ?CPU: INTER XEON 3.33 GHZ,2處理器，
?? ?MEM:16G
?? ?OS:windows server ENTERPRISE 64位；
?? ?進行以下測試時沒有其它業務在運行。
?? ?2.1 設置使用5個并行進行查詢統計，看到COST=608
?? ?SQL> select /*+ PARALLEL(5) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?2.2 設置使用10個并行進行查詢統計，看到COST=304，減少了一半
?? ?SQL>
?? ?SQL> select /*+ PARALLEL(10) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 10 because of hint
?? ?2.3 設置使用30個并行進行查詢統計，看到COST=101，減少到1/3
?? ?SQL> select /*+ PARALLEL(30) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 30 because of hint
?? ?2.4 設置使用30個并行進行查詢統計，看到COST=76，減少到并行度為10 時的1/4
?? ?SQL> select /*+ PARALLEL(40) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 40 because of hint
?? ?我經過測試，一直測試到120個并行度時，都還是正常的。看來在此服務器上，并不能測試出
?? ?此數據查詢的合適并行度是多少。因為服務器為空閑。并且性能也不錯。
?? ?直到測試出錯誤：ORA-00020:maximum number of processes (150) exceeded 錯誤
?? ?我的參數? processes=150，后來修改成300，再測試下面內容
?? ?下面使用了更大的表進行測試：直到測試到25-30個并行度時，COST才沒有按比例下降。
?? ?所以我認為多少個最優的并行度，并不適合不同的表。并且也不能做為優化查詢的一個指標。
?? ?因為在正式的產品服務器中，性能是在變化的。只要能滿足當前業務需求就好。
?? ?SQL> set autotrance onlytrace
?? ?SQL> set autotrace traceonly;
?? ?SQL> set linesize 800;
?? ?SQL> select /*+ PARALLEL(1) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1994127684
?? ?----------------------------------------------------------------------
?? ?| Id? | Operation????????? | Name??? | Rows? | Cost (%CPU)| Time???? |
?? ?----------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?? |???????? |???? 1 | 75474?? (1)| 00:15:06 |
?? ?|?? 1 |? SORT AGGREGATE??? |???????? |???? 1 |??????????? |????????? |
?? ?|?? 2 |?? TABLE ACCESS FULL| PERSION |??? 20M| 75474?? (1)| 00:15:06 |
?? ?----------------------------------------------------------------------
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ?? 1? recursive calls
?? ??? ??? ?? 1? db block gets
?? ??? ? 278268? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(2) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 41876?? (1)| 00:01:24 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 41876?? (1)| 00:01:24 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 41876?? (1)| 00:01:24 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 2 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ?? 7? recursive calls
?? ??? ??? ?220? db block gets
?? ??? ? 442739? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(3) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 27918?? (1)| 00:00:56 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 27918?? (1)| 00:00:56 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 27918?? (1)| 00:00:56 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 3 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 12? recursive calls
?? ??? ??? ?237? db block gets
?? ??? ? 455506? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(4) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 20938?? (1)| 00:00:42 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 20938?? (1)| 00:00:42 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 20938?? (1)| 00:00:42 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 4 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 15? recursive calls
?? ??? ??? ?238? db block gets
?? ??? ? 456257? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(5) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 16751?? (1)| 00:00:34 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 16751?? (1)| 00:00:34 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 16751?? (1)| 00:00:34 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 5 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 18? recursive calls
?? ??? ??? ?238? db block gets
?? ??? ? 456257? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(6) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 13959?? (1)| 00:00:28 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 13959?? (1)| 00:00:28 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 13959?? (1)| 00:00:28 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 6 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 21? recursive calls
?? ??? ??? ?255? db block gets
?? ??? ? 469024? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(7) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 11965?? (1)| 00:00:24 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 11965?? (1)| 00:00:24 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 11965?? (1)| 00:00:24 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 7 because of hint
?? ?SQL> select /*+ PARALLEL(20) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 4188?? (1)| 00:00:09 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 4188?? (1)| 00:00:09 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 4188?? (1)| 00:00:09 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 20 because of hint
?? ?SQL> select /*+ PARALLEL(30) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 2792?? (1)| 00:00:06 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 2792?? (1)| 00:00:06 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 2792?? (1)| 00:00:06 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 30 because of hint
?? ?SQL> select /*+ PARALLEL(25) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 3350?? (1)| 00:00:07 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 3350?? (1)| 00:00:07 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 3350?? (1)| 00:00:07 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 25 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 76? recursive calls
?? ??? ??? ?501? db block gets
?? ??? ? 653770? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL>
-----------------------------------------------------------------------
3.針對PARALLEL_DEGREE_POLICY的三個值，分別演示它們的效果。<br>
答： PARALLEL_DEGREE_POLICY 三個值為：
?? ?MANUAL:?? ??? ?手動方式，也是默認方式，ORACLE不會擅自去調整并行度
?? ?LIMITED:?? ?限制方式?? ?如果為限制方式，即使你指定并行度大于此
?? ?auto:?? ??? ?自動方式
?? ?3.1.1 查詢當前參數值
?? ?SQL> set linesize 800;
?? ?SQL> show parameter parallel_degree;
?? ?NAME?????????????????????? TYPE??????????? VALUE
?? ?----------------------? -------------- ---------------
?? ?parallel_degree_limit???? string????????? CPU
?? ?parallel_degree_policy??? string????????? MANUAL
?? ?SQL>
?? ?3.1.2 建立測試表，使用HINT 指定并行并查詢，
?? ?SQL> drop table t purge;
?? ?Table dropped.
?? ?SQL> create table t as select * from dba_objects;
?? ?Table created.
?? ?看到這時ORACLE使用了我指定的并行度進行查詢數據；
?? ?3.1.3 指定表默認并行度，再進行查詢
?? ?SQL> alter table t parallel(degree 4);
?? ?Table altered.
?? ?select table_name,degree from user_tables t where t.TABLE_NAME='T'
?? ??? ?TABLE_NAME?? ?DEGREE
?? ??? ?--------------------
?? ?1?? ?T?? ????????? 4
?? ?SQL> set autotrace off;
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC??????????? LAST_QUERY SESSION_TOTAL
?? ?------------------- ---------- -------------
?? ?Allocation Height??? 0???????????? 0
?? ?SQL> select /*+ PARALLEL(t 4) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC????? LAST_QUERY SESSION_TOTAL
?? ?------------- ---------- -------------
?? ?Allocation Height??? 4???????????? 0
?? ?SQL>
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC????????? LAST_QUERY SESSION_TOTAL
?? ?---------------? ---------- -------------
?? ?Allocation Height??? 4???????????? 0
?? ?SQL> select /*+ PARALLEL(t 6) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ? LAST_QUERY SESSION_TOTAL
?? ?------------?? ? ---------- -------------
?? ?Allocation Height?? 6???????????? 0
?? ?從上面的3次查詢可以看出，不管是我指定并行度或是使用默認的并行度，真正在查詢時，
?? ?ORACLE都是按我指定的或是按默認的并行度進行查詢，并沒有干預。
?? ?3.2.1 把參數 PARALLEL_DEGREE_POLICY 設置成LIMITED
?? ?SQL> ALTER SESSION SET PARALLEL_DEGREE_POLICY=LIMITED;
?? ?SQL> select? count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC???? LAST_QUERY SESSION_TOTAL
?? ?----------- ---------- -------------
?? ?Allocation Height?? 4???????????? 0
?? ?SQL> select /*+ PARALLEL(t 60) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 60????????????? 0
?? ?SQL> select /*+ PARALLEL(t 100) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 100????????????? 0
?? ?SQL> select /*+ PARALLEL(t 200) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 200????????????? 0
?? ?SQL> select /*+ PARALLEL(t 2900) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 48????????????? 0
?? ?SQL>
?? ?因為服務器性能不錯的原因，上面我的測試，開始一直加大并行度，ORACLE都沒有干預，但我加大到 2900時（這時大于參數PROCESSES)
?? ?ORACLE開始干預了，系統認為 48 是最好的。
?? ?3.3.1 把參數 PARALLEL_DEGREE_POLICY 設置成AUTO
?? ?ALTER SESSION SET PARALLEL_DEGREE_POLICY=AUTO;
?? ?SQL> ALTER SESSION SET PARALLEL_DEGREE_POLICY=AUTO;
?? ?Session altered.
?? ?SQL> select? count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 4????????? 0
?? ?SQL> select /*+ PARALLEL(t 20) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 20????????? 0
?? ?SQL> select /*+ PARALLEL(t 100) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 100????????? 0
?? ?SQL> select /*+ PARALLEL(t 2900) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 263????????? 0
?? ?在參數設置成AUTO時，在不指定并行度時，ORACLE 使用了4個，說明它認為4個并行就夠了。
?? ?在我指定并行度為20，100時，ORACLE也沒有干預。但我指定為2900時，ORACLE干預了。
?? ?這時使用了263個并行度進行查詢。
-----------------------------------------------------------------------
4.用一個并行的SQL示例，比較10391事件和 V$PQ_TQSTAT結果的異同。<br>
?? ?4.1 設置測試環境
?? ?SQL> alter session set sql_trace=true;
?? ?Session altered.
?? ?SQL> alter session set tracefile_identifier='tang'
?? ?? 2? ;
?? ?Session altered.
?? ?SQL>
?? ?SQL> alter session set events '10391 trace name context forever,level 128';
?? ?Session altered.
?? ?分別用不同的并行度，做3次查詢
?? ?SQL> select /*+parallel(t,1) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> select /*+parallel(t,8) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> select /*+parallel(t,10) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL>
?? ?SQL> alter session set events '10391 trace name context off';
?? ?Session altered.
?? ?SQL> select name,value from v$diag_info where name='Default Trace File';
?? ??? ?D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_ora_5368.trc
?? ?4.2 跟蹤文件日志內容
?? ?----------------------
?? ?Trace file D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_p005_3736_tang.trc
?? ?Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
?? ?With the Partitioning, OLAP, Data Mining and Real Application Testing options
?? ?Windows NT Version V6.0 Service Pack 2
?? ?CPU???????????????? : 24 - type 8664, 12 Physical Cores
?? ?Process Affinity??? : 0x0x0000000000000000
?? ?Memory (Avail/Total): Ph:4637M/16370M, Ph+PgF:24304M/32827M
?? ?Instance name: orcl
?? ?Redo thread mounted by this instance: 1
?? ?Oracle process number: 41
?? ?Windows thread id: 3736, image: ORACLE.EXE (P005)
?? ?*** 2013-11-30 14:05:08.454
?? ?*** SESSION ID:(350.17) 2013-11-30 14:05:08.454
?? ?*** CLIENT ID:() 2013-11-30 14:05:08.454
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:08.454
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:08.454
?? ?*** ACTION NAME:() 2013-11-30 14:05:08.454
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=42 dep=1 uid=84 oct=3 lid=84 tim=7871753515351 hv=1066695699 ad='2af83f3f8' sqlid='dvwddqnzt8z0m'
?? ?select /*+parallel(t,6) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=52,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871753515349
?? ?EXEC #509548072:c=0,e=6166,p=0,cr=234,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871753525406
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=234 pr=0 pw=0 time=5559 us)'
?? ?STAT #509548072 id=5 cnt=12988 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=234 pr=0 pw=0 time=41304 us cost=56 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=12988 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=234 pr=0 pw=0 time=14657 us cost=56 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=223,dep=1,type=1,tim=7871753525884
?? ?*** 2013-11-30 14:05:20.326
?? ?*** SESSION ID:(350.19) 2013-11-30 14:05:20.326
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:20.326
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:20.326
?? ?*** ACTION NAME:() 2013-11-30 14:05:20.326
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=42 dep=1 uid=84 oct=3 lid=84 tim=7871765390288 hv=2567766901 ad='2ad8b95d8' sqlid='4dgjnm6chu0vp'
?? ?select /*+parallel(t,8) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=64,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871765390286
?? ?EXEC #509548072:c=0,e=9483,p=0,cr=150,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871765400080
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=150 pr=0 pw=0 time=5034 us)'
?? ?STAT #509548072 id=5 cnt=7876 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=150 pr=0 pw=0 time=31296 us cost=42 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=7876 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=150 pr=0 pw=0 time=10265 us cost=42 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=216,dep=1,type=1,tim=7871765400981
?? ?*** 2013-11-30 14:05:24.195
?? ?*** SESSION ID:(350.21) 2013-11-30 14:05:24.195
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:24.195
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:24.195
?? ?*** ACTION NAME:() 2013-11-30 14:05:24.195
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=43 dep=1 uid=84 oct=3 lid=84 tim=7871769259701 hv=3631007758 ad='2b095bdf8' sqlid='cw04bdmc6tk0f'
?? ?select /*+parallel(t,10) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=63,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871769259699
?? ?EXEC #509548072:c=0,e=9216,p=0,cr=180,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871769269208
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=180 pr=0 pw=0 time=5288 us)'
?? ?STAT #509548072 id=5 cnt=8383 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=180 pr=0 pw=0 time=33455 us cost=34 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=8383 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=180 pr=0 pw=0 time=11851 us cost=34 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=345,dep=1,type=1,tim=7871769270106
?? ?4.2 使用日志分析工具處理后的跟蹤文件日志內容
?? ?tkprof D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_p005_3736_tang.trc
?? ?SQL ID: cw04bdmc6tk0f Plan Hash: 3126468333
?? ?select /*+parallel(t,10) */ count(0)
?? ?from
?? ? t
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?Execute????? 1????? 0.00?????? 0.01????????? 0????????? 3????????? 0?????????? 0
?? ?Fetch??????? 2????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 1
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 4????? 0.00?????? 0.01????????? 0????????? 3????????? 0?????????? 1
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 1????????? 1????????? 1? SORT AGGREGATE (cr=3 pr=0 pw=0 time=13765 us)
?? ??? ??? ?10???????? 10???????? 10?? PX COORDINATOR? (cr=3 pr=0 pw=0 time=13057 us)
?? ??? ??? ? 0????????? 0????????? 0??? PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???? SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=2)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS FULL T (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=2)
?? ?********************************************************************************
?? ?查詢V$PQ_TQSTAT
?? ?SQL> SELECT dfo_number,tq_id,server_type,num_rows,bytes,process FROM V$PQ_tqstat;
?? ?DFO_NUMBER????? TQ_ID SERVER_TYPE?? NUM_ROWS????? BYTES PROCESS
?? ?---------- ---------- ------------- ---------- ---------- ------------------------------------
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P005
?? ??? ??? ? 1????????? 0 Producer?? ??? ??? ?1???????? 36?? ?P007
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P003
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P009
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P004
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P008
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P006
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P000
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P001
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P002
?? ??? ??? ? 1????????? 0 Consumer???????? 10??????? 360?? ?QC
?? ?11 rows selected.
?? ?SQL>
?? ?在性能視圖中可以看到，使用了10個并發進程。
-----------------------------------------------------------------------
5.分別演示一個DDL和DML操作的并行執行示例。<br>
5.1 測試使用DDL
?? ?SQL> alter session set events '10046 trace name context forever,level 12';
?? ?Session altered.
?? ?SQL> drop table t5 purge;
?? ?Table dropped.
?? ?SQL> create table t5 parallel 4 as select * from dba_objects;
?? ?Table created.
?? ?SQL> create index idx_t5_obj_id on t5(object_id) parallel 4;
?? ?Index created.
?? ?SQL> alter session set events '10046 trace name context off';
?? ?Session altered.
?? ?SQL> select name,value from v$diag_info where name='Default Trace File';
?? ?NAME
?? ?--------------------------------------------------------------------------------
?? ?VALUE
?? ?--------------------------------------------------------------------------------
?? ?Default Trace File
?? ?D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_ora_5708.trc
SQL>
?? ?5.2 從跟蹤文件中，生成文件
?? ?C:\Users\Administrator>tkprof D:\app\oracle\diag\rdbms\orcl\orcl\trace\orcl_ora_
?? ?5708.trc d:\tang.prof
?? ?TKPROF: Release 11.2.0.3.0 - Development on 星期六 11月 30 16:07:58 2013
?? ?Copyright (c) 1982, 2011, Oracle and/or its affiliates.? All rights reserved.
?? ?C:\Users\Administrator>
?? ?文件內容如下：
?? ?從跟蹤文件中的內容可以看到，使用了4個并行：
?? ?create table t5 parallel 4 as select * from dba_objects
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.01?????? 0.02????????? 0????????? 0????????? 0?????????? 0
?? ?Execute????? 1????? 0.42?????? 0.90????????? 0???????? 51??????? 408?????? 76386
?? ?Fetch??????? 0????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 2????? 0.43?????? 0.92????????? 0???????? 51??????? 408?????? 76386
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=14 pr=0 pw=0 time=697718 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (RANDOM) :TQ20001 (cr=0 pr=0 pw=0 time=0 us cost=137 size=15800310 card=76330)
?? ??? ??? ? 0????????? 0????????? 0??? LOAD AS SELECT? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???? VIEW? DBA_OBJECTS (cr=0 pr=0 pw=0 time=0 us cost=137 size=15800310 card=76330)
?? ??? ??? ? 0????????? 0????????? 0????? UNION-ALL? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS BY INDEX ROWID SUM$ (cr=2 pr=0 pw=0 time=29 us cost=1 size=11 card=1)
?? ??? ??? ? 1????????? 1????????? 1??????? INDEX UNIQUE SCAN I_SUM$_1 (cr=1 pr=0 pw=0 time=15 us cost=0 size=0 card=1)(object id 1002)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS BY INDEX ROWID OBJ$ (cr=0 pr=0 pw=0 time=0 us cost=3 size=30 card=1)
?? ??? ??? ? 0????????? 0????????? 0??????? INDEX RANGE SCAN I_OBJ1 (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=1)(object id 36)
?? ??? ??? ? 0????????? 0????????? 0?????? BUFFER SORT (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???????? PX SEND ROUND-ROBIN :TQ20000 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ? 76379????? 76379????? 76379????????? FILTER? (cr=9 pr=0 pw=0 time=461741 us)
?? ??? ? 76379????? 76379????? 76379?????????? PX COORDINATOR? (cr=9 pr=0 pw=0 time=289402 us)
?? ??? ??? ? 0????????? 0????????? 0??????????? PX SEND QC (RANDOM) :TQ10002 (cr=0 pr=0 pw=0 time=0 us cost=78 size=9006114 card=76323)
?? ??? ??? ? 0????????? 0????????? 0???????????? HASH JOIN? (cr=0 pr=0 pw=0 time=0 us cost=78 size=9006114 card=76323)
?? ??? ??? ? 0????????? 0????????? 0????????????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0?????????????? PX SEND BROADCAST :TQ10001 (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0??????????????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0???????????????? TABLE ACCESS FULL USER$ (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0????????????? HASH JOIN? (cr=0 pr=0 pw=0 time=0 us cost=75 size=7708623 card=76323)
?? ??? ??? ? 0????????? 0????????? 0?????????????? BUFFER SORT (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??????????????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=1 size=2288 card=104)
?? ??? ??? ? 0????????? 0????????? 0???????????????? PX SEND BROADCAST :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=1 size=2288 card=104)
?? ??? ??? 104??????? 104??????? 104????????????????? INDEX FULL SCAN I_USER2 (cr=1 pr=0 pw=0 time=125 us cost=1 size=2288 card=104)(object id 47)
?? ??? ??? ? 0????????? 0????????? 0?????????????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=73 size=6029517 card=76323)
?? ??? ??? ? 0????????? 0????????? 0??????????????? TABLE ACCESS FULL OBJ$ (cr=0 pr=0 pw=0 time=0 us cost=73 size=6029517 card=76323)
?? ??? ??? ? 0????????? 0????????? 0?????????? NESTED LOOPS? (cr=0 pr=0 pw=0 time=0 us cost=1 size=29 card=1)
?? ??? ??? ? 0????????? 0????????? 0??????????? INDEX SKIP SCAN I_USER2 (cr=0 pr=0 pw=0 time=0 us cost=1 size=20 card=1)(object id 47)
?? ??? ??? ? 0????????? 0????????? 0??????????? INDEX RANGE SCAN I_OBJ4 (cr=0 pr=0 pw=0 time=0 us cost=0 size=9 card=1)(object id 39)
?? ??? ??? ? 0????????? 0????????? 0?????? NESTED LOOPS? (cr=0 pr=0 pw=0 time=0 us cost=4 size=273 card=7)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL LINK$ (cr=0 pr=0 pw=0 time=0 us cost=2 size=154 card=7)
?? ??? ??? ? 0????????? 0????????? 0??????? TABLE ACCESS CLUSTER USER$ (cr=0 pr=0 pw=0 time=0 us cost=0 size=17 card=1)
?? ??? ??? ? 0????????? 0????????? 0???????? INDEX UNIQUE SCAN I_USER# (cr=0 pr=0 pw=0 time=0 us cost=0 size=0 card=1)(object id 11)
?? ?......
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=5 pr=0 pw=0 time=73817 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (ORDER) :TQ10001 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??? INDEX BUILD NON UNIQUE IDX_T5_OBJ_ID (cr=0 pr=0 pw=0 time=0 us)(object id 0)
?? ??? ??? ? 0????????? 0????????? 0???? SORT CREATE INDEX (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0?????? PX SEND RANGE :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL T5 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ?Elapsed times include waiting on following events:
?? ?? Event waited on???????????????????????????? Times?? Max. Wait? Total Waited
?? ?? ----------------------------------------?? Waited? ----------? ------------
?? ?? PX Deq: Join ACK??????????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Parse Reply???????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Execute Reply????????????????????????? 82??????? 0.01????????? 0.06
?? ?? PX Deq: Table Q qref??????????????????????????? 4??????? 0.00????????? 0.00
?? ?? db file scattered read????????????????????????? 6??????? 0.00????????? 0.00
?? ?? reliable message??????????????????????????????? 7??????? 0.00????????? 0.00
?? ?? enq: CR - block range reuse ckpt??????????????? 3??????? 0.00????????? 0.00
?? ?? log file sync?????????????????????????????????? 1??????? 0.00????????? 0.00
?? ?? PX Deq: Signal ACK EXT????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Slave Session Stats???????????????????? 8??????? 0.00????????? 0.00
?? ?? enq: PS - contention??????????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message to client?????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message from client???????????????????? 1?????? 20.17???????? 20.17
?? ?********************************************************************************
?? ?create index idx_t5_obj_id on t5(object_id) parallel 4
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.01?????? 0.00????????? 0????????? 1????????? 0?????????? 0
?? ?Execute????? 1????? 0.01?????? 0.11???????? 23????????? 9??????? 965?????????? 0
?? ?Fetch??????? 0????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 2????? 0.03?????? 0.11???????? 23???????? 10??????? 965?????????? 0
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=5 pr=0 pw=0 time=73817 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (ORDER) :TQ10001 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??? INDEX BUILD NON UNIQUE IDX_T5_OBJ_ID (cr=0 pr=0 pw=0 time=0 us)(object id 0)
?? ??? ??? ? 0????????? 0????????? 0???? SORT CREATE INDEX (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0?????? PX SEND RANGE :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL T5 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ?Elapsed times include waiting on following events:
?? ?? Event waited on???????????????????????????? Times?? Max. Wait? Total Waited
?? ?? ----------------------------------------?? Waited? ----------? ------------
?? ?? PX Deq: Join ACK??????????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Parse Reply???????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Execute Reply????????????????????????? 82??????? 0.01????????? 0.06
?? ?? PX Deq: Table Q qref??????????????????????????? 4??????? 0.00????????? 0.00
?? ?? db file scattered read????????????????????????? 6??????? 0.00????????? 0.00
?? ?? reliable message??????????????????????????????? 7??????? 0.00????????? 0.00
?? ?? enq: CR - block range reuse ckpt??????????????? 3??????? 0.00????????? 0.00
?? ?? log file sync?????????????????????????????????? 1??????? 0.00????????? 0.00
?? ?? PX Deq: Signal ACK EXT????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Slave Session Stats???????????????????? 8??????? 0.00????????? 0.00
?? ?? enq: PS - contention??????????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message to client?????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message from client???????????????????? 1?????? 20.17???????? 20.17
?? ?********************************************************************************
?? ?做DML 操作時使用并行，進行一個并行插入的測試：
?? ?SQL> explain plan for insert /*+ parallel(t5 10) */ into t5 select /*+ parallel(t 4) */ * from t;
?? ?Explained.
?? ?SQL> select * from table(dbms_xplan.display);
?? ?SQL> set linesize 100;
?? ?SQL> select * from table(dbms_xplan.display);
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?Plan hash value: 3050126167
?? ?----------------------------------------------------------------------------------------------------
?? ?--------------
?? ?| Id? | Operation??????????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT
?? ?| PQ Distrib |
?? ?----------------------------------------------------------------------------------------------------
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?|?? 0 | INSERT STATEMENT???????? |????????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |??????? |
?? ?|??????????? |
?? ?|?? 1 |? LOAD TABLE CONVENTIONAL | T5?????? |?????? |?????? |??????????? |????????? |??????? |
?? ?|??????????? |
?? ?|?? 2 |?? PX COORDINATOR???????? |????????? |?????? |?????? |??????????? |????????? |??????? |
?? ?|??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM)?? | :TQ10000 | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | P->S
?? ?| QC (RAND)? |
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?|?? 4 |???? PX BLOCK ITERATOR??? |????????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | PCWC
?? ?|??????????? |
?? ?|?? 5 |????? TABLE ACCESS FULL?? | T??????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | PCWP
?? ?|??????????? |
?? ?----------------------------------------------------------------------------------------------------
?? ?12 rows selected.
?? ?SQL>
?? ?從上面的執行計劃中看到，從表T中查詢，及插入T5表，都用到了 并行處理。
與50位技術專家面對面20年技術見證，附贈技術全景圖
2.就自己本機的硬件情況，通過SQL示例，來找到最優的并行度。<br>
3.針對PARALLEL_DEGREE_POLICY的三個值，分別演示它們的效果。<br>
4.用一個并行的SQL示例，比較10391事件和 V$PQ_TQSTAT結果的異同。<br>
5.分別演示一個DDL和DML操作的并行執行示例。<br>
===============================================================
1.給出一個2表關聯的并行查詢執行計劃，并畫出并行數據流圖。<br>
答：
SQL> set linesize 8000;
SQL> set autotrace traceonly;
SQL> select /*+ PARALLEL(d 2) PARALLEL(e 2) */ d.dname,e.* from scott.dept d inner join scott.emp e on d.deptno=e.deptno;
14 rows selected.
Execution Plan
----------------------------------------------------------
Plan hash value: 197865614
-----------------------------------------------------------------------------------------------------------------
| Id? | Operation?????????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
-----------------------------------------------------------------------------------------------------------------
|?? 0 | SELECT STATEMENT??????? |????????? |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |??????? |????? |??? |
|?? 1 |? PX COORDINATOR???????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |??? |
|?? 2 |?? PX SEND QC (RANDOM)?? | :TQ10001 |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |? Q1,01 | P->S | QC (RAND)? |
|*? 3 |??? HASH JOIN??????????? |????????? |??? 14 |?? 714 |???? 5? (20)| 00:00:01 |? Q1,01 | PCWP |??? |
|?? 4 |???? PX RECEIVE????????? |????????? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWP |??? |
|?? 5 |????? PX SEND BROADCAST? | :TQ10000 |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | P->P | BROADCAST? |
|?? 6 |?????? PX BLOCK ITERATOR |????????? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | PCWC |??? |
|?? 7 |??????? TABLE ACCESS FULL| DEPT???? |???? 4 |??? 52 |???? 2?? (0)| 00:00:01 |? Q1,00 | PCWP |??? |
|?? 8 |???? PX BLOCK ITERATOR?? |????????? |??? 14 |?? 532 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWC |??? |
|?? 9 |????? TABLE ACCESS FULL? | EMP????? |??? 14 |?? 532 |???? 2?? (0)| 00:00:01 |? Q1,01 | PCWP |??? |
-----------------------------------------------------------------------------------------------------------------
Predicate Information (identified by operation id):
---------------------------------------------------
?? 3 - access("D"."DEPTNO"="E"."DEPTNO")
Statistics
----------------------------------------------------------
??????? 176? recursive calls
????????? 2? db block gets
??????? 116? consistent gets
???????? 10? physical reads
????????? 0? redo size
?????? 1758? bytes sent via SQL*Net to client
??????? 524? bytes received via SQL*Net from client
????????? 2? SQL*Net roundtrips to/from client
???????? 16? sorts (memory)
????????? 0? sorts (disk)
???????? 14? rows processed
（并行數據流示意圖請看附件）
-----------------------------------------------------------------------
2.就自己本機的硬件情況，通過SQL示例，來找到最優的并行度。<br>
?? ?使用了公司內部的測試服務器，性能上用來做一般的測試服務器應該還算可以：
?? ?配置：
?? ?CPU: INTER XEON 3.33 GHZ,2處理器，
?? ?MEM:16G
?? ?OS:windows server ENTERPRISE 64位；
?? ?進行以下測試時沒有其它業務在運行。
?? ?2.1 設置使用5個并行進行查詢統計，看到COST=608
?? ?SQL> select /*+ PARALLEL(5) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 608?? (0)| 00:00:02 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?2.2 設置使用10個并行進行查詢統計，看到COST=304，減少了一半
?? ?SQL>
?? ?SQL> select /*+ PARALLEL(10) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 304?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 10 because of hint
?? ?2.3 設置使用30個并行進行查詢統計，看到COST=101，減少到1/3
?? ?SQL> select /*+ PARALLEL(30) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|?? 101?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 30 because of hint
?? ?2.4 設置使用30個并行進行查詢統計，看到COST=76，減少到并行度為10 時的1/4
?? ?SQL> select /*+ PARALLEL(40) */ c_id,c_name from mcard.cards ;
?? ?155048 rows selected.
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 542627410
?? ?--------------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation??????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT???? |????????? |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |??????? |????? |???????? |
?? ?|?? 1 |? PX COORDINATOR????? |????????? |?????? |?????? |??????????? |????????? |??????? |????? |???????? |
?? ?|?? 2 |?? PX SEND QC (RANDOM)| :TQ10000 |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 3 |??? PX BLOCK ITERATOR |????????? |?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | PCWC |???????? |
?? ?|?? 4 |???? TABLE ACCESS FULL| cards?? ?|?? 154K|? 2114K|??? 76?? (0)| 00:00:01 |? Q1,00 | PCWP |???????? |
?? ?--------------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 40 because of hint
?? ?我經過測試，一直測試到120個并行度時，都還是正常的。看來在此服務器上，并不能測試出
?? ?此數據查詢的合適并行度是多少。因為服務器為空閑。并且性能也不錯。
?? ?直到測試出錯誤：ORA-00020:maximum number of processes (150) exceeded 錯誤
?? ?我的參數? processes=150，后來修改成300，再測試下面內容
?? ?下面使用了更大的表進行測試：直到測試到25-30個并行度時，COST才沒有按比例下降。
?? ?所以我認為多少個最優的并行度，并不適合不同的表。并且也不能做為優化查詢的一個指標。
?? ?因為在正式的產品服務器中，性能是在變化的。只要能滿足當前業務需求就好。
?? ?SQL> set autotrance onlytrace
?? ?SQL> set autotrace traceonly;
?? ?SQL> set linesize 800;
?? ?SQL> select /*+ PARALLEL(1) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1994127684
?? ?----------------------------------------------------------------------
?? ?| Id? | Operation????????? | Name??? | Rows? | Cost (%CPU)| Time???? |
?? ?----------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?? |???????? |???? 1 | 75474?? (1)| 00:15:06 |
?? ?|?? 1 |? SORT AGGREGATE??? |???????? |???? 1 |??????????? |????????? |
?? ?|?? 2 |?? TABLE ACCESS FULL| PERSION |??? 20M| 75474?? (1)| 00:15:06 |
?? ?----------------------------------------------------------------------
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ?? 1? recursive calls
?? ??? ??? ?? 1? db block gets
?? ??? ? 278268? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(2) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 41876?? (1)| 00:01:24 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 41876?? (1)| 00:01:24 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 41876?? (1)| 00:01:24 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 2 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ?? 7? recursive calls
?? ??? ??? ?220? db block gets
?? ??? ? 442739? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(3) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 27918?? (1)| 00:00:56 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 27918?? (1)| 00:00:56 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 27918?? (1)| 00:00:56 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 3 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 12? recursive calls
?? ??? ??? ?237? db block gets
?? ??? ? 455506? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(4) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 20938?? (1)| 00:00:42 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 20938?? (1)| 00:00:42 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 20938?? (1)| 00:00:42 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 4 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 15? recursive calls
?? ??? ??? ?238? db block gets
?? ??? ? 456257? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(5) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 16751?? (1)| 00:00:34 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 16751?? (1)| 00:00:34 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 16751?? (1)| 00:00:34 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 5 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 18? recursive calls
?? ??? ??? ?238? db block gets
?? ??? ? 456257? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(6) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 13959?? (1)| 00:00:28 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 13959?? (1)| 00:00:28 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 13959?? (1)| 00:00:28 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 6 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 21? recursive calls
?? ??? ??? ?255? db block gets
?? ??? ? 469024? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL> select /*+ PARALLEL(7) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 | 11965?? (1)| 00:00:24 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M| 11965?? (1)| 00:00:24 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M| 11965?? (1)| 00:00:24 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 7 because of hint
?? ?SQL> select /*+ PARALLEL(20) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 4188?? (1)| 00:00:09 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 4188?? (1)| 00:00:09 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 4188?? (1)| 00:00:09 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 20 because of hint
?? ?SQL> select /*+ PARALLEL(30) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 2792?? (1)| 00:00:06 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 2792?? (1)| 00:00:06 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 2792?? (1)| 00:00:06 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 30 because of hint
?? ?SQL> select /*+ PARALLEL(25) */ count(0) from persion p;
?? ?Execution Plan
?? ?----------------------------------------------------------
?? ?Plan hash value: 1284080732
?? ?--------------------------------------------------------------------------------------------------------
?? ?| Id? | Operation????????????? | Name???? | Rows? | Cost (%CPU)| Time???? |??? TQ? |IN-OUT| PQ Distrib |
?? ?--------------------------------------------------------------------------------------------------------
?? ?|?? 0 | SELECT STATEMENT?????? |????????? |???? 1 |? 3350?? (1)| 00:00:07 |??????? |????? |??????????? |
?? ?|?? 1 |? SORT AGGREGATE??????? |????????? |???? 1 |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 2 |?? PX COORDINATOR?????? |????????? |?????? |??????????? |????????? |??????? |????? |??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM) | :TQ10000 |???? 1 |??????????? |????????? |? Q1,00 | P->S | QC (RAND)? |
?? ?|?? 4 |???? SORT AGGREGATE???? |????????? |???? 1 |??????????? |????????? |? Q1,00 | PCWP |??????????? |
?? ?|?? 5 |????? PX BLOCK ITERATOR |????????? |??? 20M|? 3350?? (1)| 00:00:07 |? Q1,00 | PCWC |??????????? |
?? ?|?? 6 |?????? TABLE ACCESS FULL| PERSION? |??? 20M|? 3350?? (1)| 00:00:07 |? Q1,00 | PCWP |??????????? |
?? ?--------------------------------------------------------------------------------------------------------
?? ?Note
?? ?-----
?? ??? - Degree of Parallelism is 25 because of hint
?? ?Statistics
?? ?----------------------------------------------------------
?? ??? ??? ? 76? recursive calls
?? ??? ??? ?501? db block gets
?? ??? ? 653770? consistent gets
?? ??? ? 277516? physical reads
?? ??? ??? ?? 0? redo size
?? ??? ??? ?529? bytes sent via SQL*Net to client
?? ??? ??? ?524? bytes received via SQL*Net from client
?? ??? ??? ?? 2? SQL*Net roundtrips to/from client
?? ??? ??? ?? 0? sorts (memory)
?? ??? ??? ?? 0? sorts (disk)
?? ??? ??? ?? 1? rows processed
?? ?SQL>
-----------------------------------------------------------------------
3.針對PARALLEL_DEGREE_POLICY的三個值，分別演示它們的效果。<br>
答： PARALLEL_DEGREE_POLICY 三個值為：
?? ?MANUAL:?? ??? ?手動方式，也是默認方式，ORACLE不會擅自去調整并行度
?? ?LIMITED:?? ?限制方式?? ?如果為限制方式，即使你指定并行度大于此
?? ?auto:?? ??? ?自動方式
?? ?3.1.1 查詢當前參數值
?? ?SQL> set linesize 800;
?? ?SQL> show parameter parallel_degree;
?? ?NAME?????????????????????? TYPE??????????? VALUE
?? ?----------------------? -------------- ---------------
?? ?parallel_degree_limit???? string????????? CPU
?? ?parallel_degree_policy??? string????????? MANUAL
?? ?SQL>
?? ?3.1.2 建立測試表，使用HINT 指定并行并查詢，
?? ?SQL> drop table t purge;
?? ?Table dropped.
?? ?SQL> create table t as select * from dba_objects;
?? ?Table created.
?? ?看到這時ORACLE使用了我指定的并行度進行查詢數據；
?? ?3.1.3 指定表默認并行度，再進行查詢
?? ?SQL> alter table t parallel(degree 4);
?? ?Table altered.
?? ?select table_name,degree from user_tables t where t.TABLE_NAME='T'
?? ??? ?TABLE_NAME?? ?DEGREE
?? ??? ?--------------------
?? ?1?? ?T?? ????????? 4
?? ?SQL> set autotrace off;
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC??????????? LAST_QUERY SESSION_TOTAL
?? ?------------------- ---------- -------------
?? ?Allocation Height??? 0???????????? 0
?? ?SQL> select /*+ PARALLEL(t 4) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC????? LAST_QUERY SESSION_TOTAL
?? ?------------- ---------- -------------
?? ?Allocation Height??? 4???????????? 0
?? ?SQL>
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC????????? LAST_QUERY SESSION_TOTAL
?? ?---------------? ---------- -------------
?? ?Allocation Height??? 4???????????? 0
?? ?SQL> select /*+ PARALLEL(t 6) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ? LAST_QUERY SESSION_TOTAL
?? ?------------?? ? ---------- -------------
?? ?Allocation Height?? 6???????????? 0
?? ?從上面的3次查詢可以看出，不管是我指定并行度或是使用默認的并行度，真正在查詢時，
?? ?ORACLE都是按我指定的或是按默認的并行度進行查詢，并沒有干預。
?? ?3.2.1 把參數 PARALLEL_DEGREE_POLICY 設置成LIMITED
?? ?SQL> ALTER SESSION SET PARALLEL_DEGREE_POLICY=LIMITED;
?? ?SQL> select? count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC???? LAST_QUERY SESSION_TOTAL
?? ?----------- ---------- -------------
?? ?Allocation Height?? 4???????????? 0
?? ?SQL> select /*+ PARALLEL(t 60) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 60????????????? 0
?? ?SQL> select /*+ PARALLEL(t 100) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 100????????????? 0
?? ?SQL> select /*+ PARALLEL(t 200) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 200????????????? 0
?? ?SQL> select /*+ PARALLEL(t 2900) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?STATISTIC?? ??? ??? ?LAST_QUERY?? ??? ?SESSION_TOTAL
?? ?-----------?? ??? ??? ?----------?? ??? ?-------------
?? ?Allocation Height?? 48????????????? 0
?? ?SQL>
?? ?因為服務器性能不錯的原因，上面我的測試，開始一直加大并行度，ORACLE都沒有干預，但我加大到 2900時（這時大于參數PROCESSES)
?? ?ORACLE開始干預了，系統認為 48 是最好的。
?? ?3.3.1 把參數 PARALLEL_DEGREE_POLICY 設置成AUTO
?? ?ALTER SESSION SET PARALLEL_DEGREE_POLICY=AUTO;
?? ?SQL> ALTER SESSION SET PARALLEL_DEGREE_POLICY=AUTO;
?? ?Session altered.
?? ?SQL> select? count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 4????????? 0
?? ?SQL> select /*+ PARALLEL(t 20) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 20????????? 0
?? ?SQL> select /*+ PARALLEL(t 100) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 100????????? 0
?? ?SQL> select /*+ PARALLEL(t 2900) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> SELECT *? FROM V$PQ_SESSTAT WHERE STATISTIC='Allocation Height';
?? ?STATISTIC?? ??? ??? ?LAST_QUERY SESSION_TOTAL
?? ?--------?? ??? ??? ?---------- -------------
?? ?Allocation Height?? 263????????? 0
?? ?在參數設置成AUTO時，在不指定并行度時，ORACLE 使用了4個，說明它認為4個并行就夠了。
?? ?在我指定并行度為20，100時，ORACLE也沒有干預。但我指定為2900時，ORACLE干預了。
?? ?這時使用了263個并行度進行查詢。
-----------------------------------------------------------------------
4.用一個并行的SQL示例，比較10391事件和 V$PQ_TQSTAT結果的異同。<br>
?? ?4.1 設置測試環境
?? ?SQL> alter session set sql_trace=true;
?? ?Session altered.
?? ?SQL> alter session set tracefile_identifier='tang'
?? ?? 2? ;
?? ?Session altered.
?? ?SQL>
?? ?SQL> alter session set events '10391 trace name context forever,level 128';
?? ?Session altered.
?? ?分別用不同的并行度，做3次查詢
?? ?SQL> select /*+parallel(t,1) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> select /*+parallel(t,8) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL> select /*+parallel(t,10) */ count(0) from t;
?? ?? COUNT(0)
?? ?----------
?? ??? ? 76386
?? ?SQL>
?? ?SQL> alter session set events '10391 trace name context off';
?? ?Session altered.
?? ?SQL> select name,value from v$diag_info where name='Default Trace File';
?? ??? ?D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_ora_5368.trc
?? ?4.2 跟蹤文件日志內容
?? ?----------------------
?? ?Trace file D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_p005_3736_tang.trc
?? ?Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
?? ?With the Partitioning, OLAP, Data Mining and Real Application Testing options
?? ?Windows NT Version V6.0 Service Pack 2
?? ?CPU???????????????? : 24 - type 8664, 12 Physical Cores
?? ?Process Affinity??? : 0x0x0000000000000000
?? ?Memory (Avail/Total): Ph:4637M/16370M, Ph+PgF:24304M/32827M
?? ?Instance name: orcl
?? ?Redo thread mounted by this instance: 1
?? ?Oracle process number: 41
?? ?Windows thread id: 3736, image: ORACLE.EXE (P005)
?? ?*** 2013-11-30 14:05:08.454
?? ?*** SESSION ID:(350.17) 2013-11-30 14:05:08.454
?? ?*** CLIENT ID:() 2013-11-30 14:05:08.454
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:08.454
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:08.454
?? ?*** ACTION NAME:() 2013-11-30 14:05:08.454
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=42 dep=1 uid=84 oct=3 lid=84 tim=7871753515351 hv=1066695699 ad='2af83f3f8' sqlid='dvwddqnzt8z0m'
?? ?select /*+parallel(t,6) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=52,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871753515349
?? ?EXEC #509548072:c=0,e=6166,p=0,cr=234,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871753525406
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=234 pr=0 pw=0 time=5559 us)'
?? ?STAT #509548072 id=5 cnt=12988 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=234 pr=0 pw=0 time=41304 us cost=56 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=12988 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=234 pr=0 pw=0 time=14657 us cost=56 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=223,dep=1,type=1,tim=7871753525884
?? ?*** 2013-11-30 14:05:20.326
?? ?*** SESSION ID:(350.19) 2013-11-30 14:05:20.326
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:20.326
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:20.326
?? ?*** ACTION NAME:() 2013-11-30 14:05:20.326
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=42 dep=1 uid=84 oct=3 lid=84 tim=7871765390288 hv=2567766901 ad='2ad8b95d8' sqlid='4dgjnm6chu0vp'
?? ?select /*+parallel(t,8) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=64,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871765390286
?? ?EXEC #509548072:c=0,e=9483,p=0,cr=150,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871765400080
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=150 pr=0 pw=0 time=5034 us)'
?? ?STAT #509548072 id=5 cnt=7876 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=150 pr=0 pw=0 time=31296 us cost=42 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=7876 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=150 pr=0 pw=0 time=10265 us cost=42 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=216,dep=1,type=1,tim=7871765400981
?? ?*** 2013-11-30 14:05:24.195
?? ?*** SESSION ID:(350.21) 2013-11-30 14:05:24.195
?? ?*** SERVICE NAME:(orcl) 2013-11-30 14:05:24.195
?? ?*** MODULE NAME:(SQL*Plus) 2013-11-30 14:05:24.195
?? ?*** ACTION NAME:() 2013-11-30 14:05:24.195
?? ?
?? ?=====================
?? ?PARSING IN CURSOR #509548072 len=43 dep=1 uid=84 oct=3 lid=84 tim=7871769259701 hv=3631007758 ad='2b095bdf8' sqlid='cw04bdmc6tk0f'
?? ?select /*+parallel(t,10) */ count(0) from t
?? ?END OF STMT
?? ?PARSE #509548072:c=0,e=63,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871769259699
?? ?EXEC #509548072:c=0,e=9216,p=0,cr=180,cu=0,mis=0,r=0,dep=1,og=1,plh=3126468333,tim=7871769269208
?? ?STAT #509548072 id=1 cnt=0 pid=0 pos=1 obj=0 op='SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=2 cnt=0 pid=1 pos=1 obj=0 op='PX COORDINATOR? (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=3 cnt=0 pid=2 pos=1 obj=0 op='PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)'
?? ?STAT #509548072 id=4 cnt=1 pid=3 pos=1 obj=0 op='SORT AGGREGATE (cr=180 pr=0 pw=0 time=5288 us)'
?? ?STAT #509548072 id=5 cnt=8383 pid=4 pos=1 obj=0 op='PX BLOCK ITERATOR (cr=180 pr=0 pw=0 time=33455 us cost=34 size=0 card=76386)'
?? ?STAT #509548072 id=6 cnt=8383 pid=5 pos=1 obj=96047 op='TABLE ACCESS FULL T (cr=180 pr=0 pw=0 time=11851 us cost=34 size=0 card=76386)'
?? ?CLOSE #509548072:c=0,e=345,dep=1,type=1,tim=7871769270106
?? ?4.2 使用日志分析工具處理后的跟蹤文件日志內容
?? ?tkprof D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_p005_3736_tang.trc
?? ?SQL ID: cw04bdmc6tk0f Plan Hash: 3126468333
?? ?select /*+parallel(t,10) */ count(0)
?? ?from
?? ? t
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?Execute????? 1????? 0.00?????? 0.01????????? 0????????? 3????????? 0?????????? 0
?? ?Fetch??????? 2????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 1
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 4????? 0.00?????? 0.01????????? 0????????? 3????????? 0?????????? 1
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 1????????? 1????????? 1? SORT AGGREGATE (cr=3 pr=0 pw=0 time=13765 us)
?? ??? ??? ?10???????? 10???????? 10?? PX COORDINATOR? (cr=3 pr=0 pw=0 time=13057 us)
?? ??? ??? ? 0????????? 0????????? 0??? PX SEND QC (RANDOM) :TQ10000 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???? SORT AGGREGATE (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=2)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS FULL T (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=2)
?? ?********************************************************************************
?? ?查詢V$PQ_TQSTAT
?? ?SQL> SELECT dfo_number,tq_id,server_type,num_rows,bytes,process FROM V$PQ_tqstat;
?? ?DFO_NUMBER????? TQ_ID SERVER_TYPE?? NUM_ROWS????? BYTES PROCESS
?? ?---------- ---------- ------------- ---------- ---------- ------------------------------------
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P005
?? ??? ??? ? 1????????? 0 Producer?? ??? ??? ?1???????? 36?? ?P007
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P003
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P009
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P004
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P008
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P006
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P000
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P001
?? ??? ??? ? 1????????? 0 Producer????????? 1???????? 36?? ?P002
?? ??? ??? ? 1????????? 0 Consumer???????? 10??????? 360?? ?QC
?? ?11 rows selected.
?? ?SQL>
?? ?在性能視圖中可以看到，使用了10個并發進程。
-----------------------------------------------------------------------
5.分別演示一個DDL和DML操作的并行執行示例。<br>
5.1 測試使用DDL
?? ?SQL> alter session set events '10046 trace name context forever,level 12';
?? ?Session altered.
?? ?SQL> drop table t5 purge;
?? ?Table dropped.
?? ?SQL> create table t5 parallel 4 as select * from dba_objects;
?? ?Table created.
?? ?SQL> create index idx_t5_obj_id on t5(object_id) parallel 4;
?? ?Index created.
?? ?SQL> alter session set events '10046 trace name context off';
?? ?Session altered.
?? ?SQL> select name,value from v$diag_info where name='Default Trace File';
?? ?NAME
?? ?--------------------------------------------------------------------------------
?? ?VALUE
?? ?--------------------------------------------------------------------------------
?? ?Default Trace File
?? ?D:\APP\ORACLE\diag\rdbms\orcl\orcl\trace\orcl_ora_5708.trc
SQL>
?? ?5.2 從跟蹤文件中，生成文件
?? ?C:\Users\Administrator>tkprof D:\app\oracle\diag\rdbms\orcl\orcl\trace\orcl_ora_
?? ?5708.trc d:\tang.prof
?? ?TKPROF: Release 11.2.0.3.0 - Development on 星期六 11月 30 16:07:58 2013
?? ?Copyright (c) 1982, 2011, Oracle and/or its affiliates.? All rights reserved.
?? ?C:\Users\Administrator>
?? ?文件內容如下：
?? ?從跟蹤文件中的內容可以看到，使用了4個并行：
?? ?create table t5 parallel 4 as select * from dba_objects
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.01?????? 0.02????????? 0????????? 0????????? 0?????????? 0
?? ?Execute????? 1????? 0.42?????? 0.90????????? 0???????? 51??????? 408?????? 76386
?? ?Fetch??????? 0????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 2????? 0.43?????? 0.92????????? 0???????? 51??????? 408?????? 76386
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=14 pr=0 pw=0 time=697718 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (RANDOM) :TQ20001 (cr=0 pr=0 pw=0 time=0 us cost=137 size=15800310 card=76330)
?? ??? ??? ? 0????????? 0????????? 0??? LOAD AS SELECT? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???? VIEW? DBA_OBJECTS (cr=0 pr=0 pw=0 time=0 us cost=137 size=15800310 card=76330)
?? ??? ??? ? 0????????? 0????????? 0????? UNION-ALL? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS BY INDEX ROWID SUM$ (cr=2 pr=0 pw=0 time=29 us cost=1 size=11 card=1)
?? ??? ??? ? 1????????? 1????????? 1??????? INDEX UNIQUE SCAN I_SUM$_1 (cr=1 pr=0 pw=0 time=15 us cost=0 size=0 card=1)(object id 1002)
?? ??? ??? ? 0????????? 0????????? 0?????? TABLE ACCESS BY INDEX ROWID OBJ$ (cr=0 pr=0 pw=0 time=0 us cost=3 size=30 card=1)
?? ??? ??? ? 0????????? 0????????? 0??????? INDEX RANGE SCAN I_OBJ1 (cr=0 pr=0 pw=0 time=0 us cost=2 size=0 card=1)(object id 36)
?? ??? ??? ? 0????????? 0????????? 0?????? BUFFER SORT (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???????? PX SEND ROUND-ROBIN :TQ20000 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ? 76379????? 76379????? 76379????????? FILTER? (cr=9 pr=0 pw=0 time=461741 us)
?? ??? ? 76379????? 76379????? 76379?????????? PX COORDINATOR? (cr=9 pr=0 pw=0 time=289402 us)
?? ??? ??? ? 0????????? 0????????? 0??????????? PX SEND QC (RANDOM) :TQ10002 (cr=0 pr=0 pw=0 time=0 us cost=78 size=9006114 card=76323)
?? ??? ??? ? 0????????? 0????????? 0???????????? HASH JOIN? (cr=0 pr=0 pw=0 time=0 us cost=78 size=9006114 card=76323)
?? ??? ??? ? 0????????? 0????????? 0????????????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0?????????????? PX SEND BROADCAST :TQ10001 (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0??????????????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0???????????????? TABLE ACCESS FULL USER$ (cr=0 pr=0 pw=0 time=0 us cost=2 size=1768 card=104)
?? ??? ??? ? 0????????? 0????????? 0????????????? HASH JOIN? (cr=0 pr=0 pw=0 time=0 us cost=75 size=7708623 card=76323)
?? ??? ??? ? 0????????? 0????????? 0?????????????? BUFFER SORT (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??????????????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=1 size=2288 card=104)
?? ??? ??? ? 0????????? 0????????? 0???????????????? PX SEND BROADCAST :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=1 size=2288 card=104)
?? ??? ??? 104??????? 104??????? 104????????????????? INDEX FULL SCAN I_USER2 (cr=1 pr=0 pw=0 time=125 us cost=1 size=2288 card=104)(object id 47)
?? ??? ??? ? 0????????? 0????????? 0?????????????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=73 size=6029517 card=76323)
?? ??? ??? ? 0????????? 0????????? 0??????????????? TABLE ACCESS FULL OBJ$ (cr=0 pr=0 pw=0 time=0 us cost=73 size=6029517 card=76323)
?? ??? ??? ? 0????????? 0????????? 0?????????? NESTED LOOPS? (cr=0 pr=0 pw=0 time=0 us cost=1 size=29 card=1)
?? ??? ??? ? 0????????? 0????????? 0??????????? INDEX SKIP SCAN I_USER2 (cr=0 pr=0 pw=0 time=0 us cost=1 size=20 card=1)(object id 47)
?? ??? ??? ? 0????????? 0????????? 0??????????? INDEX RANGE SCAN I_OBJ4 (cr=0 pr=0 pw=0 time=0 us cost=0 size=9 card=1)(object id 39)
?? ??? ??? ? 0????????? 0????????? 0?????? NESTED LOOPS? (cr=0 pr=0 pw=0 time=0 us cost=4 size=273 card=7)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL LINK$ (cr=0 pr=0 pw=0 time=0 us cost=2 size=154 card=7)
?? ??? ??? ? 0????????? 0????????? 0??????? TABLE ACCESS CLUSTER USER$ (cr=0 pr=0 pw=0 time=0 us cost=0 size=17 card=1)
?? ??? ??? ? 0????????? 0????????? 0???????? INDEX UNIQUE SCAN I_USER# (cr=0 pr=0 pw=0 time=0 us cost=0 size=0 card=1)(object id 11)
?? ?......
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=5 pr=0 pw=0 time=73817 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (ORDER) :TQ10001 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??? INDEX BUILD NON UNIQUE IDX_T5_OBJ_ID (cr=0 pr=0 pw=0 time=0 us)(object id 0)
?? ??? ??? ? 0????????? 0????????? 0???? SORT CREATE INDEX (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0?????? PX SEND RANGE :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL T5 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ?Elapsed times include waiting on following events:
?? ?? Event waited on???????????????????????????? Times?? Max. Wait? Total Waited
?? ?? ----------------------------------------?? Waited? ----------? ------------
?? ?? PX Deq: Join ACK??????????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Parse Reply???????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Execute Reply????????????????????????? 82??????? 0.01????????? 0.06
?? ?? PX Deq: Table Q qref??????????????????????????? 4??????? 0.00????????? 0.00
?? ?? db file scattered read????????????????????????? 6??????? 0.00????????? 0.00
?? ?? reliable message??????????????????????????????? 7??????? 0.00????????? 0.00
?? ?? enq: CR - block range reuse ckpt??????????????? 3??????? 0.00????????? 0.00
?? ?? log file sync?????????????????????????????????? 1??????? 0.00????????? 0.00
?? ?? PX Deq: Signal ACK EXT????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Slave Session Stats???????????????????? 8??????? 0.00????????? 0.00
?? ?? enq: PS - contention??????????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message to client?????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message from client???????????????????? 1?????? 20.17???????? 20.17
?? ?********************************************************************************
?? ?create index idx_t5_obj_id on t5(object_id) parallel 4
?? ?call???? count?????? cpu??? elapsed?????? disk????? query??? current??????? rows
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?Parse??????? 1????? 0.01?????? 0.00????????? 0????????? 1????????? 0?????????? 0
?? ?Execute????? 1????? 0.01?????? 0.11???????? 23????????? 9??????? 965?????????? 0
?? ?Fetch??????? 0????? 0.00?????? 0.00????????? 0????????? 0????????? 0?????????? 0
?? ?------- ------? -------- ---------- ---------- ---------- ----------? ----------
?? ?total??????? 2????? 0.03?????? 0.11???????? 23???????? 10??????? 965?????????? 0
?? ?Misses in library cache during parse: 1
?? ?Optimizer mode: ALL_ROWS
?? ?Parsing user id: 84 ?
?? ?Number of plan statistics captured: 1
?? ?Rows (1st) Rows (avg) Rows (max)? Row Source Operation
?? ?---------- ---------- ----------? ---------------------------------------------------
?? ??? ??? ? 4????????? 4????????? 4? PX COORDINATOR? (cr=5 pr=0 pw=0 time=73817 us)
?? ??? ??? ? 0????????? 0????????? 0?? PX SEND QC (ORDER) :TQ10001 (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0??? INDEX BUILD NON UNIQUE IDX_T5_OBJ_ID (cr=0 pr=0 pw=0 time=0 us)(object id 0)
?? ??? ??? ? 0????????? 0????????? 0???? SORT CREATE INDEX (cr=0 pr=0 pw=0 time=0 us)
?? ??? ??? ? 0????????? 0????????? 0????? PX RECEIVE? (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0?????? PX SEND RANGE :TQ10000 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0??????? PX BLOCK ITERATOR (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ??? ??? ? 0????????? 0????????? 0???????? TABLE ACCESS FULL T5 (cr=0 pr=0 pw=0 time=0 us cost=88 size=1231737 card=94749)
?? ?Elapsed times include waiting on following events:
?? ?? Event waited on???????????????????????????? Times?? Max. Wait? Total Waited
?? ?? ----------------------------------------?? Waited? ----------? ------------
?? ?? PX Deq: Join ACK??????????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Parse Reply???????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Execute Reply????????????????????????? 82??????? 0.01????????? 0.06
?? ?? PX Deq: Table Q qref??????????????????????????? 4??????? 0.00????????? 0.00
?? ?? db file scattered read????????????????????????? 6??????? 0.00????????? 0.00
?? ?? reliable message??????????????????????????????? 7??????? 0.00????????? 0.00
?? ?? enq: CR - block range reuse ckpt??????????????? 3??????? 0.00????????? 0.00
?? ?? log file sync?????????????????????????????????? 1??????? 0.00????????? 0.00
?? ?? PX Deq: Signal ACK EXT????????????????????????? 8??????? 0.00????????? 0.00
?? ?? PX Deq: Slave Session Stats???????????????????? 8??????? 0.00????????? 0.00
?? ?? enq: PS - contention??????????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message to client?????????????????????? 1??????? 0.00????????? 0.00
?? ?? SQL*Net message from client???????????????????? 1?????? 20.17???????? 20.17
?? ?********************************************************************************
?? ?做DML 操作時使用并行，進行一個并行插入的測試：
?? ?SQL> explain plan for insert /*+ parallel(t5 10) */ into t5 select /*+ parallel(t 4) */ * from t;
?? ?Explained.
?? ?SQL> select * from table(dbms_xplan.display);
?? ?SQL> set linesize 100;
?? ?SQL> select * from table(dbms_xplan.display);
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?Plan hash value: 3050126167
?? ?----------------------------------------------------------------------------------------------------
?? ?--------------
?? ?| Id? | Operation??????????????? | Name???? | Rows? | Bytes | Cost (%CPU)| Time???? |??? TQ? |IN-OUT
?? ?| PQ Distrib |
?? ?----------------------------------------------------------------------------------------------------
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?|?? 0 | INSERT STATEMENT???????? |????????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |??????? |
?? ?|??????????? |
?? ?|?? 1 |? LOAD TABLE CONVENTIONAL | T5?????? |?????? |?????? |??????????? |????????? |??????? |
?? ?|??????????? |
?? ?|?? 2 |?? PX COORDINATOR???????? |????????? |?????? |?????? |??????????? |????????? |??????? |
?? ?|??????????? |
?? ?|?? 3 |??? PX SEND QC (RANDOM)?? | :TQ10000 | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | P->S
?? ?| QC (RAND)? |
?? ?PLAN_TABLE_OUTPUT
?? ?----------------------------------------------------------------------------------------------------
?? ?|?? 4 |???? PX BLOCK ITERATOR??? |????????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | PCWC
?? ?|??????????? |
?? ?|?? 5 |????? TABLE ACCESS FULL?? | T??????? | 76386 |? 7310K|??? 85?? (2)| 00:00:02 |? Q1,00 | PCWP
?? ?|??????????? |
?? ?----------------------------------------------------------------------------------------------------
?? ?12 rows selected.
?? ?SQL>
?? ?從上面的執行計劃中看到，從表T中查詢，及插入T5表，都用到了 并行處理。
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