8000 Add a README and Makefile recipe for Gen_dummy_probes.pl · postgres/postgres@8292c06 · GitHub
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Add a README and Makefile recipe for Gen_dummy_probes.pl
Discussion: https://postgr.es/m/20210506035602.3akutfvvojngj3nb@alap3.anarazel.de
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‎src/backend/utils/Makefile

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cd '$(dir $@)' && rm -f $(notdir $@) && \
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$(LN_S) "../../../$(subdir)/probes.h" .
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# Recipe for rebuilding the Perl version of Gen_dummy_probes
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# Nothing depends on it, so it will never be called unless explicitly requested
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# The last two lines of the recipe format the script according to our
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# standard and put back some blank lines for improved readability.
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Gen_dummy_probes.pl: Gen_dummy_probes.sed
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perl -ni -e ' print; exit if /^\$$0/;' $@
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s2p -f $< | sed -e 1,4d -e '/# #/d' -e '$$d' >> $@
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perltidy --profile=../../tools/pgindent/perltidyrc $@
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perl -pi -e '!$$lb && ( /^\t+#/ || /^# prototypes/ ) && print qq{\n};'\
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-e '$$lb = m/^\n/; ' $@
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.PHONY: install-data
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install-data: errcodes.txt installdirs

‎src/backend/utils/README.Gen_dummy_probes

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# Generating dummy probes
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If Postgres isn't configured with dtrace enabled, we need to generate
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dummy probes for the entries in probes.d, that do nothing.
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This is accomplished in Unix via the sed script `Gen_dummy_probes.sed`. We
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used to use this in MSVC builds using the perl utility `psed`, which mimicked
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sed. However, that utility disappeared from Windows perl distributions and so
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we converted the sed script to a perl script to be used in MSVC builds.
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We still keep the sed script as the authoritative source for generating
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these dummy probes because except on Windows perl is not a hard requirement
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when building from a tarball.
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So, if you need to change the way dummy probes are generated, first change
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the sed script, and when it's working generate the perl script. This can
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be accomplished by using the perl utility s2p.
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s2p is no longer part of the perl core, so it might not be on your system,
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but it is available on CPAN and also in many package systems. e.g.
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on Fedora it can be installed using `cpan App::s2p` or
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`dnf install perl-App-s2p`.
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The Makefile contains a recipe for regenerating Gen_dummy_probes.pl, so all
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you need to do is once you have s2p installed is `make Gen_dummy_probes.pl`

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