[HACKERS] More optimization effort?
От | Tatsuo Ishii |
---|---|
Тема | [HACKERS] More optimization effort? |
Дата | |
Msg-id | 20170721.081107.2259073989173912397.t-ishii@sraoss.co.jp обсуждение исходный текст |
Ответы |
Re: [HACKERS] More optimization effort?
Re: [HACKERS] More optimization effort? |
Список | pgsql-hackers |
Currently following query does not use an index: t-ishii@localhost: psql -p 5433 test Pager usage is off. psql (9.6.3) Type "help" for help. test=# explain select * from pgbench_accounts where aid*100 < 10000; QUERY PLAN ------------------------------------------------------------------------Seq Scan on pgbench_accounts (cost=0.00..3319.00rows=33333 width=97) Filter: ((aid * 100) < 10000) (2 rows) While following one does use the index. test=# explain select * from pgbench_accounts where aid < 10000/100; QUERY PLAN --------------------------------------------------------------------------------------------------Index Scan using pgbench_accounts_pkeyon pgbench_accounts (cost=0.29..11.08 rows=102 width=97) Index Cond: (aid < 100) (2 rows) Is it worth to make our optimizer a little bit smarter to convert the the first query into the second form? Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp
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