Re: [PATCH] pg_upgrade: add --initdb option to create the new cluster automatically - Mailing list pgsql-hackers
| From | Bohyun Lee |
|---|---|
| Subject | Re: [PATCH] pg_upgrade: add --initdb option to create the new cluster automatically |
| Date | |
| Msg-id | CAMPh8MoVY5cUM+BLqBQkbL8ttHCMiVZ6Z9f3AL+K+TXSh=UP+A@mail.gmail.com Whole thread |
| In response to | Re: [PATCH] pg_upgrade: add --initdb option to create the new cluster automatically (Greg Sabino Mullane <htamfids@gmail.com>) |
| List | pgsql-hackers |
Thanks both for the reviews. v4 attached, addressing all of Greg's second-pass points and Daniel's documentation point.
Greg:
resolve_new_bindir(): dropped the last two comment lines.
prep_status text is now "Examining old cluster settings".
Test: since checksums are now the default, the old cluster is created with --no-data-checksums (a genuinely non-default value) and --locale=C. The post-upgrade checks confirm the new cluster inherited both, along with the WAL segment size, encoding, collation, ctype, and locale provider.
Test: replaced open()/print() with append_conf, and the port/socket settings now follow the framework's TCP-vs-Unix logic ($use_tcp), so Windows works too.
-O: dropped support with --initdb entirely, as you originally suggested. The partial "-c only" forwarding still broke on quoted values with spaces. pg_upgrade now rejects -O + --initdb during option parsing, with a test and a doc note.
Daniel:
Reworked the manual-initdb docs: the vague "use compatible initdb flags" is now the specific settings that must match (WAL segment size, checksums, encoding, locale), with a pointer to pg_controldata.
On in-tree vs. wrapper: these settings have to come from the old cluster's control data, which pg_upgrade already reads, a wrapper would have to rediscover the same information, and getting it wrong is exactly the failure --initdb is meant to prevent.
The patch is pgindent-clean and the full pg_upgrade TAP suite passes (including the new t/009_initdb_option.pl).
Registered in PG20-2. Branch on GitHub: https://github.com/LeeBohyun/postgres/tree/pg_upgrade_initdb
Best regards,
Bohyun
Second review pass.
Cleanly compiles and all tests pass when applied to 637aa273e (Thu Jul 16 11:56:01 2026 -0400)
/*
* resolve_new_bindir()
*
* Idempotent helper: if new_cluster.bindir has not been set by the user via
* -B, derive it from the path of the currently executing pg_upgrade binary.
* Called early by create_new_cluster_via_initdb() so that the initdb path
* is available before verify_directories() runs.
*/
Do we really need the last two lines? This is also called during the "normal" path, not just via create_new_cluster_via_initdb, so not sure why we are pointing it out here.
> prep_status("Inspecting old cluster locale for new cluster creation");
We are doing a lot more than locale though. How about:
prep_status("Examining old cluster settings");
> # Use non-default settings that --initdb must carry over to the new cluster
> # (derived from the old cluster's pg_control): data checksums and a non-default
> # WAL segment size. We check below that the new cluster inherits them.
> my $oldnode = PostgreSQL::Test::Cluster->new('old_node');
> $oldnode->init(extra => [ '--data-checksums', '--wal-segsize' => '2' ]);
But checkums ARE the default now, so for a non-default setting, we should do --no-data-checksums. Would be nice to check locale as well. That gets tricky, but maybe --locale=C is nicely portable and pretty non-default?
> my $conf = $newnode->data_dir . '/postgresql.conf';
> open(my $fh, '>>', $conf) or die "could not open $conf: $!";
Easier to use $newnode->append_conf
> print $fh "listen_addresses = ''\n";
> print $fh "unix_socket_directories = '" . $newnode->host . "'\n";
What about Win32? See .e.g $use_tcp in Cluster.pm
> * Forward only "-c name=value" options from -O to initdb. initdb accepts
I still think we just bail on supporting -O. The new code is an improvement, but fails if there are legitimate spaces in any of the args:
$ pg_upgrade --initdb -O "-c transaction_isolation='repeatable read'"
Creating new cluster with initdb ignoring non-"-c" option(s) passed via -O; only "-c" settings are forwarded to initdb for --initdb
sh: 1: Syntax error: Unterminated quoted string
*failure*
Cheers,
Greg
Attachment
pgsql-hackers by date: