postgresql/src/backend/utils
Tom Lane 1250aad425 Ensure pg_filenode_relation(0, 0) returns NULL.
Previously, a zero value for the relfilenode resulted in
a confusing error message about "unexpected duplicate".
This function returns NULL for other invalid relfilenode
values, so zero should be treated likewise.

It's been like this all along, so back-patch to all supported
branches.

Justin Pryzby

Discussion: https://postgr.es/m/20210612023324.GT16435@telsasoft.com
2021-06-12 13:29:24 -04:00
..
activity Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
adt Ensure pg_filenode_relation(0, 0) returns NULL. 2021-06-12 13:29:24 -04:00
cache Fix race condition when sharing tuple descriptors. 2021-05-29 15:12:34 +12:00
error Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
fmgr Reconsider the handling of procedure OUT parameters. 2021-06-10 17:11:36 -04:00
hash Update copyright for 2021 2021-01-02 13:06:25 -05:00
init Add function to log the memory contexts of specified backend process. 2021-04-06 13:44:15 +09:00
mb Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
misc Re-allow custom GUC names that have more than two components. 2021-06-02 18:50:23 -04:00
mmgr Restore the portal-level snapshot after procedure COMMIT/ROLLBACK. 2021-05-21 14:03:59 -04:00
resowner Refactor HMAC implementations 2021-04-03 17:30:49 +09:00
sort Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
time Initial pgindent and pgperltidy run for v14. 2021-05-12 13:14:10 -04:00
.gitignore Rearrange makefile rules for running Gen_fmgrtab.pl. 2018-05-03 17:54:18 -04:00
errcodes.txt Rethink SQLSTATE code for ERRCODE_IDLE_SESSION_TIMEOUT. 2021-01-11 14:53:42 -05:00
Gen_dummy_probes.pl Emit dummy statements for probes.d probes when disabled 2021-05-10 11:40:03 +02:00
Gen_dummy_probes.pl.prolog Tweak generation of Gen_dummy_probes.pl 2021-05-11 20:02:02 -04:00
Gen_dummy_probes.sed Emit dummy statements for probes.d probes when disabled 2021-05-10 11:40:03 +02:00
Gen_fmgrtab.pl Update copyright for 2021 2021-01-02 13:06:25 -05:00
generate-errcodes.pl Update copyright for 2021 2021-01-02 13:06:25 -05:00
Makefile Tweak generation of Gen_dummy_probes.pl 2021-05-11 20:02:02 -04:00
probes.d Update copyright for 2021 2021-01-02 13:06:25 -05:00
README.Gen_dummy_probes Tweak generation of Gen_dummy_probes.pl 2021-05-11 20:02:02 -04:00

# 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.