From: | Tino Wildenhain <tino(at)wildenhain(dot)de> |
---|---|
To: | Thomas Vatter <thomas(dot)vatter(at)network-inventory(dot)de> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: in memory views |
Date: | 2006-05-10 10:08:30 |
Message-ID: | 4461BB9E.5030607@wildenhain.de |
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Thread: | |
Lists: | pgsql-performance |
Thomas Vatter schrieb:
> Tino Wildenhain wrote:
>
>> Thomas Vatter schrieb:
>>
>>> is there a possibility for creating views or temp tables in memory to
>>> avoid disk io when user makes select operations?
>>
>>
>>
>> No need. The data will be available in OS and database caches if
>> they are really required often. If not, tune up the caches and
>> do a regular "pre select".
>>
>> Regards
>> Tino
>>
>>
>
> hmm, I am selecting a resultset with 1300 rows joined from 12 tables.
> with jdbc I am waiting 40 seconds until the first row appears. The
> following rows appear really fast but the 40 seconds are a problem.
Well you will need the equally 40 seconds to fill your hypothetical
in memory table. (even a bit more due to the creation of a datastructure).
So you can do the aproaches of semi materialized views (that are in fact
writing into a shadow table) or just prefetch your data at time - just
at the times you would refill your memory tables if they existed.
A cronjob with select/fetch should do.
Regards
Tino
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