Timeline for Why seq-scan can be much faster than index-scan and index-only-scan in this simple query?
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| May 23, 2017 at 12:40 | history | edited | CommunityBot | replaced http://stackoverflow.com/ with https://stackoverflow.com/ | |
| Aug 6, 2015 at 12:13 | comment | added | Craig Ringer | @ChrisTien An index-only scan should usually be fastest for a simple count, if the visibility map is up to date so not many heap pages have to be fetched. This is not a simple count though, there's a join involved. | |
| Aug 4, 2015 at 17:08 | history | edited | Vérace | CC BY-SA 3.0 | added 309 characters in body |
| Aug 4, 2015 at 13:57 | history | edited | Vérace | CC BY-SA 3.0 | added 342 characters in body |
| Jul 26, 2015 at 9:23 | comment | added | Chris Tien | since it is COUNT(*) in select clause, so there is no need to fetch data from the table, right? so I think index-only-scan should be the fastest one, but the result is not :-( | |
| Jul 26, 2015 at 9:14 | history | answered | Vérace | CC BY-SA 3.0 |