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ORACLE视图加上别名查询非常慢,去掉之后正常
v_gasmonthsum是个视图,select * from v_gasmonthsum t;带上t查询100s都出不来,去掉t 1秒以内就出来,执行计划一样,有哪位遇到过,这个问题反复验证过,不是偶然的
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但是通过查询select * from v_gasmonthsum t where rownum<1000速度却又恢复正常,总感觉select * from v_gasmonthsum t;这个查询方法是不是少了自动分页提取数据的功能
以下是select * from v_gasmonthsum t执行计划:不带别名t的查询计划雷同
| 1 | Plan hash value: 984768051 | ||||||||||||
| 2 | |||||||||||||
| 3 | ------------------------------------------------------------------------------------------------------------ | ||||||||||||
| 4 | | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | | ||||||||||||
| 5 | ------------------------------------------------------------------------------------------------------------ | ||||||||||||
| 6 | | 0 | SELECT STATEMENT | | 1 | 224 | 5308 (1)| 00:01:04 | | ||||||||||||
| 7 | | 1 | NESTED LOOPS | | 1 | 224 | 5308 (1)| 00:01:04 | | ||||||||||||
| 8 | | 2 | NESTED LOOPS | | 1 | 211 | 5304 (1)| 00:01:04 | | ||||||||||||
| 9 | | 3 | NESTED LOOPS | | 1 | 117 | 5298 (1)| 00:01:04 | | ||||||||||||
| # | | 4 | VIEW | VW_SQ_1 | 213 | 11076 | 4870 (1)| 00:00:59 | | ||||||||||||
| # | | 5 | HASH GROUP BY | | 213 | 11076 | 4870 (1)| 00:00:59 | | ||||||||||||
| # | |* 6 | FILTER | | | | | | | ||||||||||||
| # | | 7 | TABLE ACCESS BY INDEX ROWID| GASOUTPUTMONTHDATA | 213 | 11076 | 4870 (1)| 00:00:59 | | ||||||||||||
| # | |* 8 | INDEX FULL SCAN | IDX_GASOUTPUTMONTHDATA | 8726 | | 4766 (1)| 00:00:58 | | ||||||||||||
| # | |* 9 | TABLE ACCESS BY INDEX ROWID | GASOUTPUTMONTHDATA | 1 | 65 | 3 (0)| 00:00:01 | | ||||||||||||
| # | |* 10 | INDEX RANGE SCAN | IDX_GASOUTPUTMONTHDATA | 1 | | 2 (0)| 00:00:01 | | ||||||||||||
| # | | 11 | INLIST ITERATOR | | | | | | | ||||||||||||
| # | | 12 | TABLE ACCESS BY INDEX ROWID | GASFACMONTHDATA | 1 | 94 | 6 (0)| 00:00:01 | | ||||||||||||
| # | |* 13 | INDEX RANGE SCAN | IDX_GASFACMONTHDATA | 1 | | 5 (0)| 00:00:01 | | ||||||||||||
| # | |* 14 | VIEW PUSHED PREDICATE | VW_SQ_2 | 1 | 13 | 4 (0)| 00:00:01 | | ||||||||||||
| # | |* 15 | FILTER | | | | | | | ||||||||||||
| # | | 16 | SORT AGGREGATE | | 1 | 55 | | | | ||||||||||||
| # | |* 17 | FILTER | | | | | | | ||||||||||||
| # | |* 18 | INDEX RANGE SCAN | IDX_GASFACMONTHDATA | 1 | 55 | 4 (0)| 00:00:01 | | ||||||||||||
| # | ------------------------------------------------------------------------------------------------------------ | ||||||||||||
| # | |||||||||||||
| # | Predicate Information (identified by operation id): | ||||||||||||
| # | --------------------------------------------------- | ||||||||||||
| # | |||||||||||||
| # | 6 - filter(201801 | ||||||||||||
| # | 8 - access("G"."YEARANDMONTH">=201801 AND "G"."YEARANDMONTH" | ||||||||||||
| # | ))) | ||||||||||||
| # | filter("G"."YEARANDMONTH">=201801 AND "G"."YEARANDMONTH" | ||||||||||||
| # | ))) | ||||||||||||
| # | 9 - filter("T"."SHAREID"="MAX(SHAREID)") | ||||||||||||
| # | 10 - access("T"."PSCODE"="ITEM_1" AND "T"."OUTPUTCODE"="ITEM_3" AND "T"."YEARANDMONTH"="ITEM_2") | ||||||||||||
| # | filter("T"."YEARANDMONTH">=201801 AND "T"."YEARANDMONTH" | ||||||||||||
| # | ))) | ||||||||||||
| # | 13 - access("T"."PSCODE"="T"."PSCODE" AND "T"."OUTPUTCODE"="T"."OUTPUTCODE" AND | ||||||||||||
| # | ("T"."POLLUTANTCODE"='001' OR "T"."POLLUTANTCODE"='002' OR "T"."POLLUTANTCODE"='003') AND | ||||||||||||
| # | "T"."YEARANDMONTH"="T"."YEARANDMONTH") | ||||||||||||
| # | filter("T"."YEARANDMONTH">=201801 AND "T"."YEARANDMONTH" | ||||||||||||
| # | ))) | ||||||||||||
| # | 14 - filter(SYS_OP_UNDESCEND(SYS_OP_DESCEND("SHAREID"))="MAX(SHAREID)") | ||||||||||||
| # | 15 - filter(COUNT(*)>0 AND 201801 | ||||||||||||
| # | 17 - filter(TO_NUMBER(TO_CHAR(SYSDATE@!,'YYYYMM'))>"T"."YEARANDMONTH" AND | ||||||||||||
| # | 201801<="T"."YEARANDMONTH" AND 201801 | ||||||||||||
| # | 18 - access("G"."PSCODE"="T"."PSCODE" AND "G"."OUTPUTCODE"="T"."OUTPUTCODE" AND | ||||||||||||
| # | "G"."POLLUTANTCODE"="T"."POLLUTANTCODE" AND "G"."YEARANDMONTH"="T"."YEARANDMONTH") | ||||||||||||
| # | filter("G"."YEARANDMONTH">=201801 AND "G"."YEARANDMONTH" | ||||||||||||
| # | ))) | ||||||||||||
| # | |||||||||||||
| # | Note | ||||||||||||
| # | ----- | ||||||||||||
| # | - dynamic sampling used for this statement (level=2) | ||||||||||||
新闻名称：ORACLE视图加上别名查询非常慢,去掉之后正常
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