原始SQL：
| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263 | CREATE OR REPLACE PROCEDURE sp_upd_suppressed_emails(A_LIMIT_BULK IN PLS_INTEGER DEFAULT 2000,A_COMMIT_AFTER IN PLS_INTEGER DEFAULT 2000) isv_operation Varchar2(20) := 'START';v_last PLS_INTEGER; v_start PLS_INTEGER; v_end PLS_INTEGER; l_row PLS_INTEGER; CURSOR curs_contact IS SELECT id FROM contactWHERE active_ind = 2 and suppress_flag = 'Y' and bounce_flag = 'Y' and consumer_id in (select id from consumers where login_name IN ('ASPIRAFOCUS', 'CDFW', 'PSACSFSUSR') ) and email is not null ORDER BY id; TYPE contactId IS RECORD ( id contact.id%TYPE); TYPE v_contactId_tbl IS TABLE OF contactId INDEX BY PLS_INTEGER; v_contact v_contactId_tbl; BEGIN DBMS_OUTPUT.PUT_LINE ('start reading data..' );v_operation := 'BEFORE OPEN';OPEN curs_contact; LOOP v_operation := 'BEFORE FETCH';FETCH curs_contact BULK COLLECT INTO v_contact LIMIT A_LIMIT_BULK;v_operation := 'AFTER FETCH'; EXIT WHEN v_contact.COUNT = 0; v_start := 1; v_last := v_contact.COUNT; l_row := 0; LOOP DBMS_OUTPUT.PUT_LINE ('LOOP 2 top ');EXIT WHEN v_start > v_last;v_end := LEAST (v_start + A_COMMIT_AFTER - 1, v_last); DBMS_OUTPUT.PUT_LINE ('LOOP 2 v_start ' || v_start || ' end ' || v_end ); BEGIN v_operation := 'UPDATE_LOAD';FORALL i IN v_start .. v_end UPDATE contact SET active_ind = 1, suppress_flag = 'N', bounce_flag = 'N' WHERE id = v_contact (i).id; END;DBMS_OUTPUT.PUT_LINE ('after forall start ' || v_start || ' end ' || v_end );COMMIT;v_start := v_end + 1; END LOOP;DBMS_OUTPUT.PUT_LINE ('LOOP 2 bottom v_start ' || v_start || ' end ' || v_end );COMMIT;END LOOP;DBMS_OUTPUT.PUT_LINE ('stop reading data..' ); EXCEPTION WHEN OTHERS THEN DBMS_OUTPUT.PUT_LINE ('Exception:Others-> v_operation = ' || v_operation || ', rowcount # ' || l_row || ' SQLCODE ' || SQLCODE || ' ERR_MSG = ' || SUBSTR(SQLERRM, 1, 500) ); END sp_upd_suppressed_emails; |
原始SQL在执行过程中经过几小时未完成，查看sql统计信息：
| Stat Name | Statement Total | Per Execution | % Snap Total |
|---|---|---|---|
| Elapsed Time (ms) | 2,997,435 | 187,339.68 | 53.56 |
| CPU Time (ms) | 2,896,748 | 181,046.72 | 65.48 |
| Executions | 16 | ||
| Buffer Gets | 521,592,791 | 32,599,549.44 | 69.21 |
| Disk Reads | 10,974 | 685.88 | 1.12 |
| Parse Calls | 1 | 0.06 | 0.00 |
| Rows | 32,000 | 2,000.00 | |
| User I/O Wait Time (ms) | 2,525 | ||
| Cluster Wait Time (ms) | 1,146 | ||
| Application Wait Time (ms) | 4 | ||
| Concurrency Wait Time (ms) | 1 | ||
| Invalidations | 0 | ||
| Version Count | 1 | ||
| Sharable Mem(KB) | 51 |
Back to Plan 1(PHV: 3689516641)
Execution Plan
| Id | Operation | Name | Rows | Bytes | Cost (%CPU) | Time | Pstart | Pstop |
|---|---|---|---|---|---|---|---|---|
| 0 | UPDATE STATEMENT | 16798 (100) | ||||||
| 1 | UPDATE | CONTACT | ||||||
| 2 | PARTITION RANGE ALL | 1 | 51 | 16798 (1) | 00:00:01 | 1 | 1048575 | |
| 3 | PARTITION HASH SINGLE | 1 | 51 | 16798 (1) | 00:00:01 | KEY | KEY | |
| 4 | TABLE ACCESS FULL | CONTACT | 1 | 51 | 16798 (1) | 00:00:01 |
表数据量非常大，根据created_date时间字段分区，ID字段进行子hash分区，上面建立了基于ID字段的global hash分区索引。
从上面情况看出，原始SQL分批2000个ID进行批量update，但执行计划走的是TABLE ACCESS FULL, 并且进行了分区的PRATITION RANGE ALL操作，可以看出2000条记录的批量更新由于不能利用global hash分区索引进行检索，主要原因是由于hash分区适用于等值操作，对于范围或者批量操作，可能遍历很多hash分区，导致结果不如TABLE ACCESS FULL。
针对这种情况，根据业务逻辑，将批量条件从ID改成其他非global hash索引列，执行时间降低为5分钟。
| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556 | CREATE OR REPLACE PROCEDURE sp_upd_suppressed_emails(A_LIMIT_BULK IN PLS_INTEGER DEFAULT 2000,A_COMMIT_AFTER IN PLS_INTEGER DEFAULT 2000) isv_operation Varchar2(20) := 'START';v_last PLS_INTEGER;v_start PLS_INTEGER;v_end PLS_INTEGER;l_row PLS_INTEGER;CURSOR curs_contact IS SELECT distinct email FROM contactWHERE active_ind = 2 and suppress_flag = 'Y' and bounce_flag = 'Y'and consumer_id in (select id from consumers where login_name IN ('ASPIRAFOCUS', 'CDFW', 'PSACSFSUSR') )and email is not null ORDER BY email;TYPE contactId IS RECORD ( email contact.email%TYPE);TYPE v_contactId_tbl IS TABLE OF contactId INDEX BY PLS_INTEGER;v_contact v_contactId_tbl;v_upd_date date ;BEGINDBMS_OUTPUT.PUT_LINE ('start reading data..' );v_operation := 'BEFORE OPEN';select sysdate into v_upd_date from dual;OPEN curs_contact;LOOPv_operation := 'BEFORE FETCH';FETCH curs_contact BULK COLLECT INTO v_contact LIMIT A_LIMIT_BULK;v_operation := 'AFTER FETCH';EXIT WHEN v_contact.COUNT = 0;v_start := 1;v_last := v_contact.COUNT;l_row := 0;LOOPDBMS_OUTPUT.PUT_LINE ('LOOP 2 top ');EXIT WHEN v_start > v_last;v_end := LEAST (v_start + A_COMMIT_AFTER - 1, v_last);DBMS_OUTPUT.PUT_LINE ('LOOP 2 v_start ' || v_start || ' end ' || v_end );BEGINv_operation := 'UPDATE_LOAD';FORALL i IN v_start .. v_endUPDATE contact SET active_ind = 1, suppress_flag = 'N', bounce_flag = 'N' , modified_date = v_upd_dateWHERE email = v_contact (i).emailand active_ind = 2 and suppress_flag = 'Y' and bounce_flag = 'Y'and consumer_id in (select id from consumers where login_name IN ('ASPIRAFOCUS', 'CDFW', 'PSACSFSUSR') ) ;END;DBMS_OUTPUT.PUT_LINE ('after forall start ' || v_start || ' end ' || v_end );COMMIT;v_start := v_end + 1;END LOOP;DBMS_OUTPUT.PUT_LINE ('LOOP 2 bottom v_start ' || v_start || ' end ' || v_end );COMMIT;END LOOP;DBMS_OUTPUT.PUT_LINE ('stop reading data..' );EXCEPTIONWHEN OTHERS THENDBMS_OUTPUT.PUT_LINE ('Exception:Others-> v_operation = ' || v_operation || ', rowcount # ' || l_row || ' SQLCODE ' || SQLCODE || ' ERR_MSG = ' || SUBSTR(SQLERRM, 1, 500) );END sp_upd_suppressed_emails; |