pgsql: Modify local buffer management to request memory for local - Mailing list pgsql-committers

Log Message:
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Modify local buffer management to request memory for local buffers in blocks
of increasing size, instead of one at a time.  This reduces the memory
management overhead when num_temp_buffers is large: in the previous coding
we would actually waste 50% of the space used for temp buffers, because aset.c
would round the individual requests up to 16K.  Problem noted while studying
a performance issue reported by Steven Flatt.

Back-patch as far as 8.1 --- older versions used few enough local buffers
that the issue isn't significant for them.

Modified Files:
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    pgsql/src/backend/storage/buffer:
        localbuf.c (r1.74 -> r1.75)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/storage/buffer/localbuf.c.diff?r1=1.74&r2=1.75)