Re: Strange explain on partitioned tables - Mailing list pgsql-performance

From Gerald Fontenay
Subject Re: Strange explain on partitioned tables
Date
Msg-id 4C4DFD95.4000901@lbl.gov
Whole thread Raw
In response to Re: Strange explain on partitioned tables  ("Joshua D. Drake" <jd@commandprompt.com>)
Responses Re: Strange explain on partitioned tables  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-performance
Joshua D. Drake wrote:
On Fri, 2010-07-23 at 15:03 -0700, Gerald Fontenay wrote: 
The PostgreSQL partitioning system is aimed to support perhaps a 
hundred inherited tables.  You can expect to get poor performance on 
queries if you create 1000 of them.      
Hi,

Why is that you would expect poor performance for say 1000 or more? I 
have a ~1000 inherited tables and I don't see any significant slowdowns. 
I only ever access a single inherited table at a time though in this 
situation. I suppose I am using inheritance only for organization in 
this case...   
It is variable based on workload and as I recall has to do with the
planning time. As the number of children increases, so does the planning
time.

Joshua D. Drake

 
Thank you for your response. So if I query only my target child table, this should be "just like" any other single table wrt planning right? I have thousands of these tables. (I suppose that I'm only using inheritance for the sake of organization in this situation...)

Thanks!
Gerald

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