On 22 March 2014 05:32, Tom Lane <t...@sss.pgh.pa.us> wrote: > Thom Brown <t...@linux.com> writes: >> Is it necessary for a partial index that doesn't include the row to be >> involved in locking? > > Yes. You can't determine whether the index needs to get a new entry > without examining its metadata, and that's what the lock is mainly about.
I see. Why does this apply to deletes too? > The only possible alternative would be to take the minimum possible > lock (AccessShareLock) on each index so its metadata would hold still, > and then upgrade that to RowExclusiveLock on the one(s) we find need > insertions. This is not better; it means *more* lock management traffic > not less, and lock upgrades increase the potential for deadlocks. Yes, I can see that wouldn't be an improvement. -- Thom -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
