From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Gregory Stark <stark(at)enterprisedb(dot)com> |
Cc: | "Jeff Davis" <pgsql(at)j-davis(dot)com>, "pgsql-hackers" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: synchronized scans for VACUUM |
Date: | 2008-06-01 13:57:42 |
Message-ID: | 19398.1212328662@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Gregory Stark <stark(at)enterprisedb(dot)com> writes:
>> It will certainly not "solve" the problem. What it will do is mean that
>> the breaks are further apart and longer, which seems to me to make the
>> conflict with syncscan behavior worse not better.
> How would it make them longer? They still have the same amount of i/o to do
> scanning the indexes. I suppose they would dirty more pages which might slow
> them down?
More tuples to delete = more writes (in WAL, if not immediately in the
index itself) = longer to complete the indexscan. It's still cheaper
than doing multiple indexscans, of course, but my point is that the
index-fixing work gets concentrated.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Jonah H. Harris | 2008-06-01 14:56:10 | Re: Feedback on blog post about Replication Feature decision and its impact |
Previous Message | Dirk Riehle | 2008-06-01 13:31:44 | Re: Feedback on blog post about Replication Feature decision and its impact |