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| author | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2016-09-02 11:51:49 +0300 |
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| committer | Heikki Linnakangas <heikki.linnakangas@iki.fi> | 2016-09-02 11:51:49 +0300 |
| commit | 9cca11c915e458323d0e746c68203f2c11da0302 (patch) | |
| tree | eb45155d06c2bd9794a345ce15933fbfc69a75d4 /src/backend/utils/adt/pgstatfuncs.c | |
| parent | 9f85784cae4d057f307b83b0d33edede33434f04 (diff) | |
| download | postgresql-9cca11c915e458323d0e746c68203f2c11da0302.tar.gz postgresql-9cca11c915e458323d0e746c68203f2c11da0302.zip | |
Speed up SUM calculation in numeric aggregates.
This introduces a numeric sum accumulator, which performs better than
repeatedly calling add_var(). The performance comes from using wider digits
and delaying carry propagation, tallying positive and negative values
separately, and avoiding a round of palloc/pfree on every value. This
speeds up SUM(), as well as other standard aggregates like AVG() and
STDDEV() that also calculate a sum internally.
Reviewed-by: Andrey Borodin
Discussion: <c0545351-a467-5b76-6d46-4840d1ea8aa4@iki.fi>
Diffstat (limited to 'src/backend/utils/adt/pgstatfuncs.c')
0 files changed, 0 insertions, 0 deletions