Re: [HACKERS] Does having a NULL column automatically exclude thetable from the tupleDesc cache?
| От | Jim Nasby |
|---|---|
| Тема | Re: [HACKERS] Does having a NULL column automatically exclude thetable from the tupleDesc cache? |
| Дата | |
| Msg-id | a8c86d85-0117-ce74-5348-5ed6d17603b6@BlueTreble.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] Does having a NULL column automatically exclude thetable from the tupleDesc cache? (Ryan Murphy <ryanfmurphy@gmail.com>) |
| Ответы |
Re: [HACKERS] Does having a NULL column automatically exclude thetable from the tupleDesc cache?
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| Список | pgsql-hackers |
On 2/15/17 1:37 PM, Ryan Murphy wrote: > > attcacheoff can only be set positive for fields preceding any varlena > (typlen<0, but including the first such) or nullable values. I don't > know how much faster it is with the cache; you can measure it if your > curiosity is strong enough -- just set the first column to nullable. > > > Thanks! Maybe I'll do some benchmarks. You'll probably want to do those at a C level, bypassing the executor. I would guess that executor overhead will completely swamp the effect of the cache in most cases. -- Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX Experts in Analytics, Data Architecture and PostgreSQL Data in Trouble? Get it in Treble! http://BlueTreble.com 855-TREBLE2 (855-873-2532)
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