Re: [GENERAL] Autovacuum Improvements

Kenneth Marshall <ktm@is.rice.edu> writes:
> Not that I am aware of. Even extending the relation by one additional
> block can make a big difference in performance

Do you have any evidence to back up that assertion?

It seems a bit nontrivial to me --- not the extension part exactly, but
making sure that the space will get used promptly.  With the current
code the backend extending a relation will do subsequent inserts into
the block it just got, which is fine, but there's no mechanism for
remembering that any other newly-added blocks are available --- unless
you wanted to push them into the FSM, which could work but the current
FSM code doesn't support piecemeal addition of space, and in any case
there's some question in my mind about the concurrency cost of increasing
FSM traffic even more.

In short, it's hardly an unquestionable improvement, so we need some
evidence.
        regards, tom lane