On Mon, 3 Nov 2008, Ivan Sergio Borgonovo wrote:
I'm looking for a bit more guidance on gin index creation.
The process:
- vaccum analyze.
- start a transaction that:
- drop the triggers to update a tsvector
- drop the index on the tsvector
- fill several tables
- update the tsvector in a table with ~800K records
- recreate the gin index
- commit
To have a rough idea of the data involved:
- 800K record
- tsvector formed from concatenation of 6 fields
- total length of concatenated fields ~ 200 chars *
- average N of lexemes in tsvector 10 *
[*] guessed
2xXeon HT 3.2GHz, 4Gb RAM, SCSI RAID5
Index creation takes more than 1h.
maintenance_work_mem is still untouched. What would be a good value
to start from?
Anything else to do to improve performances?
why you didn't change maintenance_work_mem ? You can change it online just
before create index. Bulk gin index creation uses it as a buffer and you can
save a lot of IO.
All this written in the documentation and there are other parameters you
should be concerned about.
Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@xxxxxxxxxx, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83
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