Timeline for Why does adding a smallint column to a postgres query increase execution time 60X?
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
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| Jan 19, 2016 at 5:11 | comment | added | jjanes | hash join estimation was pretty thoroughly redone in 9.5.0. Can you upgrade to that and see if the problem still exists? | |
| Jan 9, 2016 at 4:59 | comment | added | Erwin Brandstetter | You should at least upgrade to the latest point release of your major version, which is currently 9.3.10. Details: postgresql.org/support/versioning And check if that makes the problem go away. | |
| Jan 8, 2016 at 22:04 | comment | added | user3416742 | cow_dev=# select version(); version ------------------------------------------------------------------------------------------------------------------------------------------------------------------- PostgreSQL 9.3.5 on x86_64-apple-darwin, compiled by i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00), 64-bit (1 row) | |
| Jan 8, 2016 at 6:41 | answer | added | J-16 SDiZ | timeline score: 3 | |
| Jan 8, 2016 at 2:16 | history | tweeted | twitter.com/StackDBAs/status/685283945940955136 | ||
| Jan 7, 2016 at 21:15 | comment | added | jjanes | Looks like a bug in the hash batches calculation. What version of PostgreSQL, including minor point release, are you running? | |
| Jan 7, 2016 at 21:03 | comment | added | András Váczi |
@a_horse_with_no_name also the hashing that precedes that join has an enormous amount of batches. It seems that work_mem is very limiting in the second case - no idea why (if the tuple width estimation if the planner is correct).
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| Jan 7, 2016 at 20:30 | comment | added | user1822 |
This is really strange. It's only the hash right join that takes so much longer. I wonder if the number of columns exceeds some threshold that causes this. You probably should post that to the Postgres performance mailing list.
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| Jan 7, 2016 at 20:18 | history | edited | user3416742 | CC BY-SA 3.0 |
Add query plans
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| Jan 7, 2016 at 19:03 | review | First posts | |||
| Jan 7, 2016 at 20:41 | |||||
| Jan 7, 2016 at 19:00 | history | asked | user3416742 | CC BY-SA 3.0 |