Re: 7.4 beta 1 getting out of swap - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: 7.4 beta 1 getting out of swap
Date
Msg-id 200308150041.h7F0fqn08208@candle.pha.pa.us
Whole thread Raw
In response to Re: 7.4 beta 1 getting out of swap  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> I can think of a number of ways we might attack this, but none seem
> especially attractive ---
> 
> 1. Have the index AMs create and switch into a special memory context
> for each call, rather than running in the main execution context.
> I am not sure this is workable at all, since the AMs tend to think they
> can create data structures that will live across calls (for example a
> btree lookup stack).  It'd be the most general solution, if we could
> make it work.
> 
> 2. Modify the index AMs so that the comparison function FmgrInfo is
> preserved across a whole query.  I think this requires changes to the
> index AM API (index_insert for instance has no provision for sharing
> data across multiple calls).  Messy, and would likely mean an initdb.
> It would probably be the fastest answer though, since lookups wouldn't
> need to be done more than once per query.

#2 seems most natural in that it formalizes something that is common for
lots of index methods.

We are only in beta1, so I think we can initdb.

> 3. Set up a long-lived cache internal to the array functions that can
> translate element type OID to the needed lookup data, and won't leak
> memory across repeated calls.  This is not the fastest or most general
> solution, but it seems the most localized and safest fix.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


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