This didn't work because when we dropped and re-established a database
connection, we did not bother to reset session-specific state such as
the statements-are-prepared flags.
The st->prepared[] array certainly needs to be flushed, and I cleared a
couple of other fields as well that couldn't possibly retain meaningful
state for a new connection.
In passing, fix some bogus comments and strange field order choices.
Per report from Robins Tharakan.
The original code wasn't careful to test the file descriptor returned by
PQsocket() for an invalid socket. If an invalid socket did turn up,
that would amount to calling FD_ISSET with fd = -1, whereby undefined
behavior can be invoked.
To fix, test file descriptor for validity and stop further processing if
that fails.
Problem noticed by Coverity.
There is an existing FD_ISSET callsite that does check for invalid
sockets beforehand, but the error message reported by it was
strerror(errno); in testing the aforementioned change, that turns out to
result in "bad socket: Success" which isn't terribly helpful. Instead
use PQerrorMessage() in both places which is more likely to contain an
useful error message.
Backpatch-through: 9.1.
If the called command fails to return data, runShellCommand forgot to
pclose() the pipe before returning. This is fairly harmless in the current
code, because pgbench would then abandon further processing of that client
thread; so no more than nclients descriptors could be leaked this way. But
it's not hard to imagine future improvements whereby that wouldn't be true.
In any case, it's sloppy coding, so patch all branches. Found by Coverity.
out immediately on any out-of-memory condition. It's rather pointless to
imagine that pgbench will be able to continue usefully after a malloc
failure, and in any case there were a number of unchecked mallocs.
writes. The first worker still uses "pgbench_log.<pid>" for the name, but
additional workers use "pgbench_log.<pid>.<serial-number>" instead.
Reported by Greg Smith.
Variables must consist of only alphabets, numerals and underscores.
We had allowed to set variables with invalid names, but could not
refer them in queries.
Thanks to Robert Haas for the review.
\shell command runs an external shell command.
\setshell also does the same and sets the result to a variable.
original patch by Michael Paquier with some editorialization by Itagaki,
and reviewed by Greg Smith.
processes of a pgbench run, when we are using -j > 1 and are emulating
threads via fork(). Otherwise the children all inherit the same random
sequence state and produce the same random-number sequence.
In the threaded case the different threads will share one RNG state, so
they will produce different subsets of one sequence, which is maybe more
correlated than a purist would like but will not be "the same". So we
leave that case alone.
First noticed by Takahiro Itagaki, and is also part of the explanation
for the pgbench misbehavior recently reported by Jaime Casanova.
are used to populate the tables with -i, but when running actual benchmark
it has values separately hard-coded in the query metacommands. This patch
makes the metacommands obtain their values from the relevant #defines.
Patch provided by Jeff Janes.
reviewed by Greg Smith and Josh Williams.
Following is the proposal from ITAGAKI Takahiro:
Pgbench is a famous tool to measure postgres performance, but nowadays
it does not work well because it cannot use multiple CPUs. On the other
hand, postgres server can use CPUs very well, so the bottle-neck of
workload is *in pgbench*.
Multi-threading would be a solution. The attached patch adds -j
(number of jobs) option to pgbench. If the value N is greater than 1,
pgbench runs with N threads. Connections are equally-divided into
them (ex. -c64 -j4 => 4 threads with 16 connections each). It can
run on POSIX platforms with pthread and on Windows with win32 threads.
Here are results of multi-threaded pgbench runs on Fedora 11 with intel
core i7 (8 logical cores = 4 physical cores * HT). -j8 (8 threads) was
the best and the tps is 4.5 times of -j1, that is a traditional result.
$ pgbench -i -s10
$ pgbench -n -S -c64 -j1 => tps = 11600.158593
$ pgbench -n -S -c64 -j2 => tps = 17947.100954
$ pgbench -n -S -c64 -j4 => tps = 26571.124001
$ pgbench -n -S -c64 -j8 => tps = 52725.470403
$ pgbench -n -S -c64 -j16 => tps = 38976.675319
$ pgbench -n -S -c64 -j32 => tps = 28998.499601
$ pgbench -n -S -c64 -j64 => tps = 26701.877815
Is it acceptable to use pthread in contrib module?
If ok, I will add the patch to the next commitfest.
pgbench_history, and pgbench_tellers, rather than just accounts, branches,
history, and tellers. This is to prevent accidental conflicts with real
application tables, as has been reported to happen at least once. Also
remove the automatic "SET search_path = public" that it did at startup,
as this seems to restrict testing flexibility without actually buying much.
Per proposal by Joshua Drake and ensuing discussion.
Joshua Drake and Tom Lane
1. -i option should run vacuum analyze only on pgbench tables, not *all*
tables in database.
2. pre-run cleanup step was DELETE FROM HISTORY then VACUUM HISTORY.
This is just a slow version of TRUNCATE HISTORY.
Simon Riggs
hazards. Instead teach these programs to prompt for a password when
necessary, just like all our other programs.
I did not bother to invent -W switches for them, since the return on
investment seems so low.
couldn't possibly HAVE_GETOPT. I believe this is the most appropriate
form of the patch submitted 2007-08-07 by Hiroshi Saito, though not
having a Windows build environment I won't know for sure till I see
the buildfarm results.
Tom Lane