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Re: Bad plan choice nestloop vs. hashjoin

From: Kenneth Marshall <ktm(at)rice(dot)edu>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Bad plan choice nestloop vs. hashjoin
Date: 2010-01-16 00:14:40
Message-ID: 20100116001440.GA12155@it.is.rice.edu (view raw or flat)
Thread:
Lists: pgsql-performance
On Fri, Jan 15, 2010 at 04:58:57PM -0600, Kevin Grittner wrote:
> Kenneth Marshall <ktm(at)rice(dot)edu> wrote:
>  
> > with the default settings
>  
> Do you mean you haven't changed any settings in your postgresql.conf
> file from their defaults?
>  
> -Kevin
> 
Sorry, here are the differences from the default:

max_connections = 100                   # (change requires restart)
shared_buffers = 256MB                  # min 128kB or max_connections*16kB
work_mem = 16MB                         # min 64kB
maintenance_work_mem = 512MB            # min 1MB
synchronous_commit = off                # immediate fsync at commit
wal_buffers = 256kB                     # min 32kB
checkpoint_segments = 30                # in logfile segments, min 1, 16MB each
seq_page_cost = 1.0                     # measured on an arbitrary scale
random_page_cost = 2.0                  # same scale as above
effective_cache_size = 12GB
log_min_duration_statement = 5000

The machine has 16GB of RAM and the DB is currently about 8GB. It
is going to grow much larger as information is acquired.

Cheers,
Ken

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