Re: [PERFORM] A Better External Sort? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PERFORM] A Better External Sort?
Date
Msg-id 29837.1128223567@sss.pgh.pa.us
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In response to Re: [PERFORM] A Better External Sort?  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: [PERFORM] A Better External Sort?
List pgsql-hackers
Martijn van Oosterhout <kleptog@svana.org> writes:
> Anyway, to bring some real info I just profiled PostgreSQL 8.1beta
> doing an index create on a 2960296 row table (3 columns, table size
> 317MB).

3 columns in the index you mean?  What were the column datatypes?
Any null values?

> The number 1 bottleneck with 41% of user time is comparetup_index.
> ...
> The thing is, I can't see anything in comparetup_index() that could
> take much time.

The index_getattr and heap_getattr macros can be annoyingly expensive.
        regards, tom lane


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