Re: Sequential disk access during VACUUM for GiST/GIN
| От | Alexander Korotkov |
|---|---|
| Тема | Re: Sequential disk access during VACUUM for GiST/GIN |
| Дата | |
| Msg-id | CAPpHfdsKWm1AbHqEs3n3s2GVHGQ4+H3ZR7KpDFG=EvqX_hsQTg@mail.gmail.com обсуждение исходный текст |
| Ответ на | Sequential disk access during VACUUM for GiST/GIN (Костя Кузнецов <chapaev28@yandex.ru>) |
| Список | pgsql-hackers |
Hi!
On Tue, Apr 29, 2014 at 2:34 PM, Костя Кузнецов <chapaev28@yandex.ru> wrote:
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With best regards,
Alexander Korotkov.
There is a task "Sequential disk access during VACUUM for GiST/GIN " in list GSOC14.Nobody is working on this task?
I didn't hear anybody is working on it.
Do I understand this task correctly?I must recode gistbulkdelete.GistBDItem *stack is must have items with sequential blkno as possible.
Yes, make gistbulkdelete and ginbulkdelete access disk sequentially while now tree is traversed in logical order. So these functions need to be completely reworked: I'm not sure GistBDItem will survive :)
The challenge is concurrency. Vacuum shouldn't block concurrent readers and writers. You can see btbulkdelete which supports sequential disk access now.
I have a question:where are access to disk in this function? ReadBufferExtended?
Yes, this function read buffer to shared memory (if it isn't already) and "pins" it.
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With best regards,
Alexander Korotkov.
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