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Re: Re: Need help in reclaiming disk space by deleting the selected records

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On 09/28/12 12:36 AM, Albe Laurenz wrote:
Yelai, Ramkumar wrote:
>7 base tables X 120 months = 840 child tables. As per your statement, If I create these many table then it will affect the performance. But as per the document (http://www.postgresql.org/docs/9.1/static/ddl-partitioning.html) constraint_exclusion will improve query performance. Please clarify me here how query planning will be expensive?
The planner will have to decide which of the 840 tables
to access.



well, really, which of the 120 tables for a given base table. he's got 7 different base tables. 120 partitions is still too many.

if I was partioning a table for 2 year retention, I'd probably do it by month, or even quarter, so there would be 24 or 8 child tables for 2 years. we use week tables for 6 months, but almost all of our activity is to the latest week and the one before that, its quite rare we need to dig back to older records..



--
john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast



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