Daniel,
concurrency is a big issue of current implementation of GiST.
But it should don't bite you for READ ops ! -hackers mailing list is a very relevant mailing list for GiST
discussions. It's pity we several times claimed to work on GiST
concurrency and recovery, but never got a chance :)
I see Neil become interested in GiST concurrency, though.
Oleg On Tue, 9 Nov 2004, Daniel Ceregatti wrote:
Hi,
It's recently come to my attention that GIST indices suffer from concurrency issues. I have already developed a dating sites using GIST for use with attributes using the intarray contrib, and for Earth distance/radius calculations using pg_sphere.
I'm wondering if I haven't shot myself in the foot here. So far, I understand that a GIST index will be locked by a backend for any DML. Basically I'm concerned that my database will not scale in the manner that I was hoping, because the sites that access the database are to be used by many multiple concurrent users, doing some DML.
I expect my site to sustain something around 1000-3000 new user acquisitions per day, all of which will account for an insert into 3 GIST indices. Additionally there will be people that will be updating their attributes and locations as well, but this will probably only account for a small fraction of the DML. We don't allow people to delete stuff.
My concern now is this concurrency issue. My question is: Is there anyone out there using a GIST index on a database where there's a lot of DML? Should I be concerned with this issue at all?
If so, what can be done to minimize the impact of heavy DML on a GIST index? I've pondered rolling all DML into queues via triggers and then de-queuing them in one transaction every so often, like 15 minutes, via cron. Any other suggestions?
I'm posting to this list because I understand that both Oleg and Teodor read it, and I found no other relevant list. If I've misposted, please accept my apology and please direct me to the appropriate list.
Thanks,
Daniel
Regards, Oleg _____________________________________________________________ Oleg Bartunov, sci.researcher, hostmaster of AstroNet, Sternberg Astronomical Institute, Moscow University (Russia) Internet: [EMAIL PROTECTED], http://www.sai.msu.su/~megera/ phone: +007(095)939-16-83, +007(095)939-23-83
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