Re: [COMMITTERS] pgsql: In COPY, insert tuples to the heap in batches. - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: [COMMITTERS] pgsql: In COPY, insert tuples to the heap in batches.
Date
Msg-id 4EBAC9AD.40603@enterprisedb.com
Whole thread Raw
In response to Re: [COMMITTERS] pgsql: In COPY, insert tuples to the heap in batches.  (Simon Riggs <simon@2ndQuadrant.com>)
List pgsql-hackers
On 09.11.2011 15:25, Simon Riggs wrote:
> On Wed, Nov 9, 2011 at 9:06 AM, Heikki Linnakangas
> <heikki.linnakangas@iki.fi>  wrote:
>> In COPY, insert tuples to the heap in batches.
>>
>> This greatly reduces the WAL volume, especially when the table is narrow.
>> The overhead of locking the heap page is also reduced. Reduced WAL traffic
>> also makes it scale a lot better, if you run multiple COPY processes at
>> the same time.
>
> Sounds good.
>
> I can't see where this applies backup blocks. If it does, can you
> document why/where/how it differs from other WAL records?

Good catch, I missed that. I copied the redo function from normal 
insertion, but missed that heap_redo() takes care of backup blocks for 
you, while heap2_redo() does not.

I'll go fix that..

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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