場景：

student 表中 10萬條數(shù)據(jù)。

從 student 表中取出所有數(shù)據(jù)，插入到 student_his 表中

優(yōu)化方法：

1.批量插入(效果明顯)

2.批量查詢(效果不明顯)

3.批量提交(效果不明顯)

4.預(yù)編譯 sql 語句(效果不明顯)

效果：

10萬條數(shù)據(jù)，普通方法 27 秒，優(yōu)化后 8 秒

測試步驟：

1.創(chuàng)建數(shù)據(jù)庫表

create tablestudent

(

student_idinteger,

student_namevarchar2(20),

salaryfloat(126)

);create unique index index_student_id onstudent(student_id);insert into student (student_id, student_name, salary) values (1, ‘test‘, 2);create tablestudent_his

(

student_idinteger,

student_namevarchar2(20),

salaryfloat(126)

);create unique index index_student_his_id on student_his(student_id);

2.準(zhǔn)備數(shù)據(jù)：

insert.pc 插入 10萬條數(shù)據(jù)

vim insert.pc

#include #include

/*插入條數(shù)*/

#define COUNTNUM 100000

/*數(shù)組大小*/

#define RECORDNUM 1000EXEC SQL INCLUDE SQLCA;voidsqlerror();

typedefstructRecord

{intstudent_id;char student_name[20];floatsalary;

}Record;intmain()

{

EXEC SQL BEGIN DECLARE SECTION;char username[20];char password[20];char db_name[20];intstudent_id;char student_name[15];floatsalary;

Record records[RECORDNUM];

EXEC SQL END DECLARE SECTION;

printf("size:%d\n",sizeof(records));int j = 0;int i = 0;int count = 1;/*出錯處理*/EXEC SQL WHENEVER SQLERROR DO sqlerror();

EXEC SQL WHENEVER NOT FOUND GOTO notfound;/*鏈接數(shù)據(jù)庫*/strcpy(username,"ngbs");

strcpy(password,"ngbs");

strcpy(db_name,"ngbs");

EXEC SQL CONNECT :username IDENTIFIED BY :password USING :db_name;/*獲取當(dāng)前最大id號，防止插入重復(fù)*/EXEC SQL SELECT max(student_id) INTO :student_id FROM student;

printf("max student_id:%d\n", student_id);for(j=0; j

{

memset (records,0, sizeof(records));for(i=0; i

{

records[i].student_id= student_id+count;

sprintf(records[i].student_name,"%s%d", "stu", student_id+i);

records[i].salary= student_id*i+0.5;//printf("student_id=%d, student_name=%s, salary=%f\n", records[i].student_id, records[i].student_name, records[i].salary);

count++;

}/*使用數(shù)組方式一次插入多條紀(jì)錄*/EXEC SQL INSERT INTO student(student_id,student_name,salary) values (:records);

}

notfound:/*提交*/EXEC SQL COMMIT WORK RELEASE;

printf("ok\n");return 0;

}voidsqlerror()

{/*出錯回滾*/EXEC SQL WHENEVER SQLERROR CONTINUE;

printf("ORACLE error detected:\n");

printf("%s\n", sqlca.sqlerrm.sqlerrmc);

EXEC SQL ROLLBACK;

}

編譯運(yùn)行腳本：

vim runin.sh

proc insert.pccc -g -o insert insert.c -L$ORACLE_HOME/lib -L$ORACLE_HOME/rdbms/lib -L/usr/lib64 -lclntsh -lm -lctime ./insert

3.對比兩種處理方法的快慢

common.pc 使用一般游標(biāo)方式

#include #include#includeEXEC SQL INCLUDE SQLCA;voidsqlerror();

typedefstructRecord

{intstudent_id;char student_name[20];floatsalary;

}Record;intmain()

{

EXEC SQL BEGIN DECLARE SECTION;char username[20];char password[20];char db_name[20];intstudent_id;char student_name[15];floatsalary;char strsql[256];

Record records;

EXEC SQL END DECLARE SECTION;

printf("records size:%d\n",sizeof(records));

memset(strsql,0, sizeof(strsql));/*出錯處理*/EXEC SQL WHENEVER SQLERROR DO sqlerror();

EXEC SQL WHENEVER NOT FOUND GOTO notfound;/*鏈接數(shù)據(jù)庫*/strcpy(username,"ngbs");

strcpy(password,"ngbs");

strcpy(db_name,"ngbs");

EXEC SQL CONNECT :username IDENTIFIED BY :password USING :db_name;/*清空*/EXEC SQL TRUNCATE TABLE student_his;/*打開游標(biāo)*/sprintf(strsql,"select * from student");

printf("strsql:%s\n", strsql);

EXEC SQL PREPARE sql_stmt FROM :strsql;if(sqlca.sqlcode)

{

printf("sql_stmt error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}

EXEC SQL DECLARE sel_cursor cursorforsql_stmt;if(sqlca.sqlcode)

{

printf("cursor error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}

EXEC SQL OPEN sel_cursor;if(sqlca.sqlcode)

{

printf("open error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}int flag = 1;while(flag)

{/*取出數(shù)據(jù) student*/EXEC SQL FETCH sel_cursor INTO :records;/*插入 student_his*/EXEC SQL INSERT INTO student_his values(:records);

}

notfound:/*提交*/EXEC SQL COMMIT WORK RELEASE;

printf("ok\n");return 0;

}voidsqlerror()

{/*出錯回滾*/EXEC SQL WHENEVER SQLERROR CONTINUE;

printf("ORACLE error detected:\n");

printf("%s\n", sqlca.sqlerrm.sqlerrmc);

EXEC SQL ROLLBACK;

exit(1);

}

編譯運(yùn)行腳本：

vim runco.sh

proc common.pccc -g -o common common.c -L$ORACLE_HOME/lib -L$ORACLE_HOME/rdbms/lib -L/usr/lib64 -lclntsh -lm -lctime ./common

fast.pc 使用游標(biāo)+結(jié)構(gòu)體數(shù)組方式

#include #include#include

/*數(shù)組大小*/

#define RECORDNUM 1000EXEC SQL INCLUDE SQLCA;voidsqlerror();

typedefstructRecord

{intstudent_id;char student_name[20];floatsalary;

}Record;intmain()

{

EXEC SQL BEGIN DECLARE SECTION;char username[20];char password[20];char db_name[20];intstudent_id;char student_name[15];floatsalary;char strsql[256];

Record records[RECORDNUM];

EXEC SQL END DECLARE SECTION;

printf("records size:%d\n",sizeof(records));

memset(strsql,0, sizeof(strsql));

memset(records,0, sizeof(records));/*出錯處理*/EXEC SQL WHENEVER SQLERROR DO sqlerror();

EXEC SQL WHENEVER NOT FOUND GOTO notfound;

EXEC ORACLE OPTION (HOLD_CURSOR=YES);/*鏈接數(shù)據(jù)庫*/strcpy(username,"ngbs");

strcpy(password,"ngbs");

strcpy(db_name,"ngbs");

EXEC SQL CONNECT :username IDENTIFIED BY :password USING :db_name;/*清空*/EXEC SQL TRUNCATE TABLE student_his;/*打開游標(biāo)*/sprintf(strsql,"select * from student");

printf("strsql:%s\n", strsql);

EXEC SQL PREPARE sql_stmt FROM :strsql;if(sqlca.sqlcode)

{

printf("sql_stmt error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}

EXEC SQL DECLARE sel_cursor cursorforsql_stmt;if(sqlca.sqlcode)

{

printf("cursor error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}

EXEC SQL OPEN sel_cursor;if(sqlca.sqlcode)

{

printf("open error[%d]", sqlca.sqlcode);returnsqlca.sqlcode;

}int flag = 1;while(flag)

{

memset(records,0, sizeof(records));/*一次取出多條數(shù)據(jù)*/EXEC SQL FETCH sel_cursor INTO :records;if(sqlca.sqlcode)

{if(sqlca.sqlcode == 100)

{

printf("NOT FOUND DATA[%d]", sqlca.sqlcode);if (sqlca.sqlerrd[2] >RECORDNUM)

{

printf("最后條數(shù)：%d\n", sqlca.sqlerrd[2] -RECORDNUM);

flag= 0;

}else{/*沒有記錄*/

break;

}

}else{

printf("fetch error[%d]", sqlca.sqlcode);break;

}

}/*一次插入多條數(shù)據(jù)*/

EXEC SQL INSERT INTO student_his values(:records);

EXEC SQL COMMIT;

}

notfound:/*提交*/EXEC SQL COMMIT WORK RELEASE;

printf("ok\n");return 0;

}voidsqlerror()

{/*出錯回滾*/EXEC SQL WHENEVER SQLERROR CONTINUE;

printf("ORACLE error detected:\n");

printf("%s\n", sqlca.sqlerrm.sqlerrmc);

EXEC SQL ROLLBACK;

exit(0);

}

編譯運(yùn)行腳本：

vim runfa.sh

proc fast.pccc -g -o fast fast.c -L$ORACLE_HOME/lib -L$ORACLE_HOME/rdbms/lib -L/usr/lib64 -lclntsh -lm -lctime ./fast

說明：

fast.pc 中調(diào)用 memset() 清空數(shù)組的操作，這個操作在10萬次插入過程中會增加2-3秒的時間。

經(jīng)過測試，數(shù)組大小 RECORDNUM 設(shè)置為 1000 左右效率比較高，沒有進(jìn)行更細(xì)致范圍的測試。

原文：https://www.cnblogs.com/etangyushan/p/12575736.html