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author | Robert Haas <rhaas@postgresql.org> | 2011-08-03 16:26:40 -0400 |
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committer | Robert Haas <rhaas@postgresql.org> | 2011-08-03 16:26:40 -0400 |
commit | 4af43ee3f165c8e4b332a7e680a44f4b7ba2d3c1 (patch) | |
tree | c75980425aaaae3144a458871139cdec9f5537ab /contrib/btree_gist/btree_gist.c | |
parent | ac36e6f71f197540b8ee83c97f338ae5e5163f30 (diff) | |
download | postgresql-4af43ee3f165c8e4b332a7e680a44f4b7ba2d3c1.tar.gz postgresql-4af43ee3f165c8e4b332a7e680a44f4b7ba2d3c1.zip |
Make pgbench use erand48() rather than random().
glibc renders random() thread-safe by wrapping a futex lock around it;
testing reveals that this limits the performance of pgbench on machines
with many CPU cores. Rather than switching to random_r(), which is
only available on GNU systems and crashes unless you use undocumented
alchemy to initialize the random state properly, switch to our built-in
implementation of erand48(), which is both thread-safe and concurrent.
Since the list of reasons not to use the operating system's erand48()
is getting rather long, rename ours to pg_erand48() (and similarly
for our implementations of lrand48() and srand48()) and just always
use those. We were already doing this on Cygwin anyway, and the
glibc implementation is not quite thread-safe, so pgbench wouldn't
be able to use that either.
Per discussion with Tom Lane.
Diffstat (limited to 'contrib/btree_gist/btree_gist.c')
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