postgresql/doc
Tom Lane e6c3ba7fbf Fix portability problem in pgbench.
The pgbench regression test supposed that srandom() with a specific value
would result in deterministic output from random(), as required by POSIX.
It emerges however that OpenBSD is too smart to be constrained by mere
standards, so their random() emits nondeterministic output anyway.
While a workaround does exist, what seems like a better fix is to stop
relying on the platform's srandom()/random() altogether, so that what
you get from --random-seed=N is not merely deterministic but platform
independent.  Hence, use a separate pg_jrand48() random sequence in
place of random().

Also adjust the regression test case that's supposed to detect
nondeterminism so that it's more likely to detect it; the original
choice of random_zipfian parameter tended to produce the same output
all the time even if the underlying behavior wasn't deterministic.

In passing, improve pgbench's docs about random_zipfian().

Back-patch to v11 where this code was introduced.

Fabien Coelho and Tom Lane

Discussion: https://postgr.es/m/4615.1547792324@sss.pgh.pa.us
2019-01-24 11:31:54 -05:00
..
src Fix portability problem in pgbench. 2019-01-24 11:31:54 -05:00
bug.template Replace @postgresql.org with @lists.postgresql.org for mailinglists 2019-01-19 19:06:35 +01:00
KNOWN_BUGS Remove extra newlines at end and beginning of files, add missing newlines 2010-08-19 05:57:36 +00:00
Makefile Remove maintainer-check target, fold into normal build 2013-10-10 20:11:56 -04:00
MISSING_FEATURES Remove extra newlines at end and beginning of files, add missing newlines 2010-08-19 05:57:36 +00:00
TODO Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00