Thread: Affect of Reindexing on Vacuum Times

I am wondering if reindexing heavily used tables can have an impact on vacuum times. If it does, will the impact be noticeable the next time I vacuum? Please note that I am doing vacuum, not vacuum full.

I am on a FreeBSD 6.1 Release, Postgresql is 8.09

Currently I seeing a phenomenon where vacuum times go up beyond 1 hour. After I re-index 3 tables, heavily used, the vacuum times stay up for the next 3 daily vacuums and then come down to 30 to 40 minutes. I am trying to see if there is a relationship between re-indexinf and vacuum times. All other things remain the same. Which means the only change I am performing is re-indexing.

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Yudhvir Singh Sidhu
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On Jul 25, 2007, at 11:53 AM, Y Sidhu wrote:
> I am wondering if reindexing heavily used tables can have an impact
> on vacuum times. If it does, will the impact be noticeable the next
> time I vacuum? Please note that I am doing vacuum, not vacuum full.
>
> I am on a FreeBSD 6.1 Release, Postgresql is 8.09
>
> Currently I seeing a phenomenon where vacuum times go up beyond 1
> hour. After I re-index 3 tables, heavily used, the vacuum times
> stay up for the next 3 daily vacuums and then come down to 30 to 40
> minutes. I am trying to see if there is a relationship between re-
> indexinf and vacuum times. All other things remain the same. Which
> means the only change I am performing is re-indexing.

Reindex will shrink index sizes, which will speed up vacuuming. But
that alone doesn't explain what you're seeing, which is rather odd.
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Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)