From: Markus Schaber <schabi@logix-tt.com>
To: Greg Stark <gsstark@mit.edu>
Cc: Orion Henry <lab@orangekids.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Large Database Design Help
Date: Fri, 10 Feb 2006 11:04:33 +0100
Message-ID: <43EC6531.60202@logix-tt.com> (raw)
In-Reply-To: <87ek2c71vl.fsf@stark.xeocode.com>
References: <43EB92DA.2080607@orangekids.org>
<87ek2c71vl.fsf@stark.xeocode.com>
Hi, Greg,
Greg Stark wrote:
>> (Aside question: if I were to find a way to use COPY and I were loading
>>data on a single client_id, would dropping just the indexes for that client_id
>>accelerate the load?)
> Dropping indexes would accelerate the load but unless you're loading a large
> number of records relative the current size I'm not sure it would be a win
> since you would then have to rebuild the index for the entire segment.
And, additionally, rebuilding a partial index with "WHERE client_id=42"
needs a full table scan, which is very slow, so temporarily dropping the
indices will not be useful if you merge the tables.
Btw, I don't know whether PostgreSQL can make use of partial indices
when building other partial indices. If yes, you could temporarily drop
all but one of the partial indices for a specific client.
HTH,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
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To: pgsql-performance@postgresql.org
Cc: schabi@logix-tt.com, gsstark@mit.edu, lab@orangekids.org
Subject: Re: Large Database Design Help
In-Reply-To: <43EC6531.60202@logix-tt.com>
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