Re: Avoiding redundant fetches of btree index metapages - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Avoiding redundant fetches of btree index metapages
Date
Msg-id 19169.1146070435@sss.pgh.pa.us
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In response to Re: Avoiding redundant fetches of btree index metapages  (Simon Riggs <simon@2ndquadrant.com>)
Responses Re: Avoiding redundant fetches of btree index metapages  (Simon Riggs <simon@2ndquadrant.com>)
List pgsql-hackers
Simon Riggs <simon@2ndquadrant.com> writes:
> Hmmm.... I'm slightly worried that frequently-churning small tables will
> be made even slower by this. What do you think?

How so?

> So we would be able to cache other items also?

Only to the extent that you can guarantee a stale cache entry isn't a
problem.  We've already done the analysis involved for the existing
metapage entries, but anything else would require more thought.  (And
more cache flush events.)

> For that case we'd save N block accesses to locate the rightmost leaf
> page.

Surely you mean log(N).
        regards, tom lane


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