Message-ID: <4E5BB423.6010303@gmail.com>
Date: Mon, 29 Aug 2011 23:45:39 +0800
From: Rural Hunter <ruralhunter@gmail.com>
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To: Kevin Grittner <Kevin.Grittner@wicourts.gov>
CC: Julio Leyva <jcleyva@hotmail.com>, pgsql-admin@postgresql.org
Subject: Re: plsql gets "out of memory"
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Hi Kevin,

Thank you very much for the quick and detailed answers/suggestions. I 
will check and try them.

于 2011/8/29 23:18, Kevin Grittner 写道:
> Good (but don't forget to change that once the bulk load is done). You 
> should probably also turn off full_page_writes and synchronous_commit. 
> I've seen benchmarks which show that this helps, even with the other 
> settings you mention. 
I forgot to mention synchronous_commit is already off and I will test 
with full_page_writes off.
>> Increase checkpoint_segments
>
> There can be paradoxical results with that.  For reasons yet to be
> determined, bulk conversion (unlike most workloads) sometimes runs
> faster with a small setting like the default.  You have to test to
> see how it works in your environment.
yes, will check that.
> Yeah, you definitely want to build those only after the data for a 
> table is loaded. I also recommend a VACUUM FREEZE ANALYZE on the 
> database unless most of these rows will be deleted or updated before 
> you run a billion database transactions. Otherwise you will get a 
> painful "anti-wraparound" autovacuum on everything, probably at a time 
> of heavy usage. 
hmm....I will try to turn autovacuum off though I didn't see any 
resource intension caused by it.
>> I have about 5G memory free on the server and have these memory
>> settings:
>> shared_buffers = 1GB
>> work_mem = 8MB
>> maintenance_work_mem = 1GB
>> effective_cache_size = 4GB
>
> Reasonable for that amount of RAM, but that's seems like
> underpowered hardware for the size of the database.  If the
> production conversion is going to be run against different hardware,
> these tests may not be giving you very good numbers for what to
> expect.
I have mysql run on the server. The memory above is just for the import 
for pgsql. I will shutdown mysql and give the memory(32G totally) to 
pgsql when I doing the performance tests.
> Network latency? Avoid encrypted connections for the load, and do 
> whatever you can to minimize latency, like attaching both machines to 
> the same switch. You can't improve performance much if you're working 
> on the things which are only using a small part of the time. 
> Identifying the source of your delays is the most important thing at 
> this point. 
No, I do the import locally on the db server so the network letency can 
be excluded.