Re: Recommendations for partitioning?

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От desmodemone
Тема Re: Recommendations for partitioning?
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Msg-id CAEs9oFm+2PH0-m4WkvB0xVB17HJaj5DcE2VXtiXoC1oDUskk4Q@mail.gmail.com
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Ответ на Recommendations for partitioning?  (Dave Johansen <davejohansen@gmail.com>)
Ответы Re: Recommendations for partitioning?
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Hi Dave,
              About the number of partitions , I didn't have so much problems with hundreds of partitions ( like 360 days in a year ).
Moreover you could bypass the overhead of trigger with a direct insert on the partition, also to have a parallel insert without to firing too much the trigger. Remember to enable the check constraints..
In my opinion it's better you try to have less rows/partition. How much is the average row length in byte ? If you will have to rebuild indexes , it will be possible , if the partition it's too big, that the maintenance_work_mem will be not enough and you will sort on disk.
I think you have to evaluate also to divide the partitions on  different tablespaces so to spread the i/o on different storage types/number ( and so on ) and to manage with different strategy the indexes (it's possible the searches will be different on "historical" partitions and on "live" partitions).
Another strategy it's also, not only to create partitions, but to shard data between more nodes.


Bye

Mat


2013/12/5 Dave Johansen <davejohansen@gmail.com>
I'm managing a database that is adding about 10-20M records per day to a table and time is a core part of most queries, so I've been looking into seeing if I need to start using partitioning based on the time column and I've found these general guidelines:

Don't use more than about 50 paritions ( http://www.postgresql.org/message-id/17147.1271696670@sss.pgh.pa.us )
The only data I found fell inline with what you'd expect (i.e. speeds up selects but slows down inserts/updates http://www.if-not-true-then-false.com/2009/performance-testing-between-partitioned-and-non-partitioned-postgresql-tables-part-3/ )

So I was thinking that partitioning based on month to keep the number of partitions low, so that would mean about 0.5G records in each table. Does that seem like a reasonable number of records in each partition? Is there anything else that I should consider or be aware of?

Thanks,
Dave

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