postgresql/src/backend/utils
Tom Lane d98ed080bb Fix small overestimation of base64 encoding output length.
pg_base64_enc_len() and its clones overestimated the output
length by up to 2 bytes, as a result of sloppy thinking about
where to divide.  No callers require a precise estimate, so
this has no consequences worse than palloc'ing a byte or two
more than necessary.  We might as well get it right though.

This bug is very ancient, dating to commit 79d78bb26 which
added encode.c.  (The other instances were presumably copied
from there.)  Still, it doesn't quite seem worth back-patching.

Oleg Tselebrovskiy

Discussion: https://postgr.es/m/f94da55286a63022150bc266afdab754@postgrespro.ru
2023-06-08 11:24:31 -04:00
..
activity rename "gss_accept_deleg" to "gss_accept_delegation". 2023-05-20 21:32:54 -04:00
adt Fix small overestimation of base64 encoding output length. 2023-06-08 11:24:31 -04:00
cache Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
error Update copyright for 2023 2023-01-02 15:00:37 -05:00
fmgr Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
hash Update copyright for 2023 2023-01-02 15:00:37 -05:00
init Remove read-only server settings lc_collate and lc_ctype 2023-06-07 16:57:06 +02:00
mb Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
misc Remove read-only server settings lc_collate and lc_ctype 2023-06-07 16:57:06 +02:00
mmgr Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
resowner Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
sort Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
time Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
.gitignore Rearrange makefile rules for running Gen_fmgrtab.pl. 2018-05-03 17:54:18 -04:00
errcodes.txt Update copyright for 2023 2023-01-02 15:00:37 -05:00
Gen_dummy_probes.pl Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
Gen_dummy_probes.pl.prolog Update copyright for 2023 2023-01-02 15:00:37 -05:00
Gen_dummy_probes.sed Update copyright for 2023 2023-01-02 15:00:37 -05:00
Gen_fmgrtab.pl Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
generate-errcodes.pl Pre-beta mechanical code beautification. 2023-05-19 17:24:48 -04:00
Makefile Update copyright for 2023 2023-01-02 15:00:37 -05:00
meson.build Update copyright for 2023 2023-01-02 15:00:37 -05:00
postprocess_dtrace.sed Update copyright for 2023 2023-01-02 15:00:37 -05:00
probes.d bufmgr: Introduce infrastructure for faster relation extension 2023-04-05 16:21:09 -07:00
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.