Обсуждение: Re: [COMMITTERS] pgsql: In COPY, insert tuples to the heap in batches.
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? There's no need for conflict processing on replay with this new WAL record type. But you should document that and alter the comments that say it is necessary. Search "conflict". -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
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