记一次全局分区索引update调优
原始SQL:
CREATE OR REPLACE PROCEDURE sp_upd_suppressed_emails
(
A_LIMIT_BULK IN PLS_INTEGER DEFAULT 2000,
A_COMMIT_AFTER IN PLS_INTEGER DEFAULT 2000
) is
v_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 contact
WHERE 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。
CREATE OR REPLACE PROCEDURE sp_upd_suppressed_emails
(
A_LIMIT_BULK IN PLS_INTEGER DEFAULT 2000,
A_COMMIT_AFTER IN PLS_INTEGER DEFAULT 2000
) is
v_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 contact
WHERE 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 ;
BEGIN
DBMS_OUTPUT.PUT_LINE ('start reading data..' );
v_operation := 'BEFORE OPEN';
select sysdate into v_upd_date from dual;
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' , modified_date = v_upd_date
WHERE email = v_contact (i).email
and 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..' );
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;