mirror of
https://git.postgresql.org/git/postgresql.git
synced 2026-03-02 10:17:02 +08:00
3a28d78089
We'd like to use TimestampDifferenceMilliseconds with the stop_time possibly being TIMESTAMP_INFINITY, but up to now it's disclaimed responsibility for overflow cases. Define it to clamp its output to the range [0, INT_MAX], handling overflow correctly. (INT_MAX rather than LONG_MAX seems appropriate, because the function is already described as being intended for calculating wait times for WaitLatch et al, and that infrastructure only handles waits up to INT_MAX. Also, this choice gets rid of cross-platform behavioral differences.) Having done that, we can replace some ad-hoc code in walreceiver.c with a simple call to TimestampDifferenceMilliseconds. While at it, fix some buglets in existing callers of TimestampDifferenceMilliseconds: basebackup_copy.c had not read the memo about TimestampDifferenceMilliseconds never returning a negative value, and postmaster.c had not read the memo about Min() and Max() being macros with multiple-evaluation hazards. Neither of these quite seem worth back-patching. Patch by me; thanks to Nathan Bossart for review. Discussion: https://postgr.es/m/3126727.1674759248@sss.pgh.pa.us
# Generating dummy probes If Postgres isn't configured with dtrace enabled, we need to generate dummy probes for the entries in probes.d, that do nothing. This is accomplished in Unix via the sed script `Gen_dummy_probes.sed`. We used to use this in MSVC builds using the perl utility `psed`, which mimicked sed. However, that utility disappeared from Windows perl distributions and so we converted the sed script to a perl script to be used in MSVC builds. We still keep the sed script as the authoritative source for generating these dummy probes because except on Windows perl is not a hard requirement when building from a tarball. So, if you need to change the way dummy probes are generated, first change the sed script, and when it's working generate the perl script. This can be accomplished by using the perl utility s2p. s2p is no longer part of the perl core, so it might not be on your system, but it is available on CPAN and also in many package systems. e.g. on Fedora it can be installed using `cpan App::s2p` or `dnf install perl-App-s2p`. The Makefile contains a recipe for regenerating Gen_dummy_probes.pl, so all you need to do is once you have s2p installed is `make Gen_dummy_probes.pl` Note that in a VPATH build this will generate the file in the vpath tree, not the source tree.