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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2021-11-28 21:32:36 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2021-11-28 21:33:07 -0500 |
| commit | 3804539e48e794781c6145c7f988f5d507418fa8 (patch) | |
| tree | 317904b43ca8c1d510b23cb8fdd7b05a75e971bc /contrib/postgres_fdw/postgres_fdw.c | |
| parent | f44ceb46ec2d8da48f6e145bf462d5620c25e079 (diff) | |
| download | postgresql-3804539e48e794781c6145c7f988f5d507418fa8.tar.gz postgresql-3804539e48e794781c6145c7f988f5d507418fa8.zip | |
Replace random(), pg_erand48(), etc with a better PRNG API and algorithm.
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
Diffstat (limited to 'contrib/postgres_fdw/postgres_fdw.c')
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 45a09337d08..f767fdcc6a1 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -5158,7 +5158,7 @@ analyze_row_processor(PGresult *res, int row, PgFdwAnalyzeState *astate) if (astate->rowstoskip <= 0) { /* Choose a random reservoir element to replace. */ - pos = (int) (targrows * sampler_random_fract(astate->rstate.randstate)); + pos = (int) (targrows * sampler_random_fract(&astate->rstate.randstate)); Assert(pos >= 0 && pos < targrows); heap_freetuple(astate->rows[pos]); } |