Restructure pg_upgrade output directories for better idempotence
38bfae3 has moved the contents written to files by pg_upgrade under a
new directory called pg_upgrade_output.d/ located in the new cluster's
data folder, and it used a simple structure made of two subdirectories
leading to a fixed structure: log/ and dump/. This design has made
weaker pg_upgrade on repeated calls, as we could get failures when
creating one or more of those directories, while potentially losing the
logs of a previous run (logs are retained automatically on failure, and
cleaned up on success unless --retain is specified). So a user would
need to clean up pg_upgrade_output.d/ as an extra step for any repeated
calls of pg_upgrade. The most common scenario here is --check followed
by the actual upgrade, but one could see a failure when specifying an
incorrect input argument value. Removing entirely the logs would have
the disadvantage of removing all the past information, even if --retain
was specified at some past step.
This result is annoying for a lot of users and automated upgrade flows.
So, rather than requiring a manual removal of pg_upgrade_output.d/, this
redesigns the set of output directories in a more dynamic way, based on
a suggestion from Tom Lane and Daniel Gustafsson. pg_upgrade_output.d/
is still the base path, but a second directory level is added, mostly
named after an ISO-8601-formatted timestamp (in short human-readable,
with milliseconds appended to the name to avoid any conflicts). The
logs and dumps are saved within the same subdirectories as previously,
as of log/ and dump/, but these are located inside the subdirectory
named after the timestamp.
The logs of a given run are removed only after a successful run if
--retain is not used, and pg_upgrade_output.d/ is kept if there are any
logs from a previous run. Note that previously, pg_upgrade would have
kept the logs even after a successful --check but that was inconsistent
compared to the case without --check when using --retain. The code in
charge of the removal of the output directories is now refactored into a
single routine.
Two TAP tests are added with some --check commands (one failure case and
one success case), to look after the issue fixed here. Note that the
tests had to be tweaked a bit to fit with the new directory structure so
as it can find any logs generated on failure. This is still going to
require a change in the buildfarm client for the case where pg_upgrade
is tested without the TAP test, though, but I'll tackle that with a
separate patch where needed.
Reported-by: Tushar Ahuja
Author: Michael Paquier
Reviewed-by: Daniel Gustafsson, Justin Pryzby
Discussion: https://postgr.es/m/77e6ecaa-2785-97aa-f229-4b6e047cbd2b@enterprisedb.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/4fff78f00910af0137f9de7532f8eb21d08ab1c3
Modified Files
--------------
doc/src/sgml/ref/pgupgrade.sgml | 5 ++-
src/bin/pg_upgrade/check.c | 2 +
src/bin/pg_upgrade/pg_upgrade.c | 69 ++++++++++++++++++++++------------
src/bin/pg_upgrade/pg_upgrade.h | 14 ++++---
src/bin/pg_upgrade/t/002_pg_upgrade.pl | 49 +++++++++++++++++++++++-
src/bin/pg_upgrade/util.c | 42 +++++++++++++++++++++
6 files changed, 150 insertions(+), 31 deletions(-)
