From: Justin Pryzby <pryzby@telsasoft.com>
To: David Gilman <davidgilman1@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org, Jim Woodworth <jimw54321@gmail.com>
Subject: Re: Warn when parallel restoring a custom dump without data offsets
Date: Mon, 22 Jun 2020 13:40:48 -0500
Message-ID: <20200622184048.GX17995@telsasoft.com> (raw)
In-Reply-To: <20200622131951.GM17995@telsasoft.com> <20200621194225.GE17995@telsasoft.com> <20200613225121.GN14879@telsasoft.com>
Adding Jim, since he ask about helping with perl.
You can read the history of the patch here:
https://commitfest.postgresql.org/28/2568/https://www.postgresql.org/message-id/flat/CALBH9DDuJ+scZc4MEvw5uO-=vRyR2=QF9+Yh=3hPEnKHWfS81A@mail....
Some context:
David is adding a test case for a bugfix he made.
We want to test parallel pg_restore of a pg_dump created with a nonseekable FD.
I suggested to make the patch smaller by creating a nonseekable FD using a pipe.
The postgres test code is using IPC::Run, but currently passing a single
argument. I think we want to change that to pass *multiple* arguments, so we
can use '>' and/or '|'. I have a patch which partially works, and another patch
which I didn't try very hard to make work, since the first part already took me
a long time..
You'll want to start with a git checkout and do:
time ./configure --enable-tap-tests ...
And apply David's patches from the above thread. The goal is to make a test
case that fails without his patch and passes with it. And maybe apply my
patches if they're useful.
I've been running the pg_dump checks like this:
time make -C src/bin/pg_dump check
On Sun, Jun 21, 2020 at 02:42:25PM -0500, Justin Pryzby wrote:
> On Sun, Jun 21, 2020 at 03:18:58PM -0400, David Gilman wrote:
> > Thank you for taking a stab at the perl thing. I took the question to
> > StackOverflow, I haven't yet looped back to try their suggestion but I
> > think there is hope by messing with the Perl references.
> > https://stackoverflow.com/questions/62086173/using-the-right-perl-array-references-with-ipcrun
>
> I finally got this to work using IPC:Run's '>' redirection operator, but it
> seems like that opens a file which *is* seekable, so doesn't work for this
> purpose. Since "cat" isn't portable (duh), the next best thing seems to be to
> pipe to perl -pe '' >ouput. Otherwise maybe your way of adding an
> --disable-seeking option is best.
>
> See if you can do anything with the attached.
[fixed patch I sent to David offlist]
[and another patch which doesn't work yet]
--
Justin
PS. The patches are named *.txt so that the patch tester doesn't try to test
them, as they're known to be incomplete.
Attachments:download all (2 files, .tar.gz)0001-Write-to-stdout-instead-of-disable-seeking.txt (text/x-diff, 1.6K) download
From 737abbc1115ee1360ac950bcf6abe1677f1eaa79 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sat, 13 Jun 2020 15:29:48 -0700
Subject: [PATCH 1/3] Write to stdout instead of --disable-seeking
---
src/bin/pg_dump/t/002_pg_dump.pl | 4 ++--
src/test/perl/TestLib.pm | 10 ++++++++--
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.plindex 2423ec5b1d..8c89488a12 100644--- a/src/bin/pg_dump/t/002_pg_dump.pl+++ b/src/bin/pg_dump/t/002_pg_dump.pl@@ -153,8 +153,8 @@ my %pgdump_runs = (
defaults_custom_format_no_seek_parallel_restore => {
test_key => 'defaults',
dump_cmd => [
- 'pg_dump', '-Fc', '-Z6', '--no-sync', '--disable-seeking',- "--file=$tempdir/defaults_custom_format_no_seek_parallel_restore.dump", 'postgres',+ [ 'pg_dump', '-Fc', '-Z6', '--no-sync', 'postgres', ],+ '>', "$tempdir/defaults_custom_format_no_seek_parallel_restore.dump", # stdout disables seeking
],
restore_cmd => [
'pg_restore', '-Fc', '--jobs=2',
diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pmindex d579d5c177..dd7b64e4c4 100644--- a/src/test/perl/TestLib.pm+++ b/src/test/perl/TestLib.pm@@ -338,8 +338,14 @@ The return value from the command is passed through.
sub run_log
{
- print("# Running: " . join(" ", @{ $_[0] }) . "\n");- return IPC::Run::run(@_);+ my @x = @{$_[0]};+ if (ref($x[0]) ne '') {+ print("# Running: " . join(" ", @{ $x[0] }) . " @x[1,scalar(@x)-1]\n");+ return IPC::Run::run(@x);+ } else {+ print("# Running: " . join(" ", @{ $_[0] }) . "\n");+ return IPC::Run::run(@_);+ }
}
=pod
--
2.24.2
0002-fix.txt (text/x-diff, 759B) download
From e855b9212f6ea178a3c5f913cec6e933e371e0b1 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Mon, 15 Jun 2020 03:28:18 -0700
Subject: [PATCH 2/3] fix
---
src/bin/pg_dump/t/002_pg_dump.pl | 2 ++
1 file changed, 2 insertions(+)
diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.plindex 8c89488a12..d28988b870 100644--- a/src/bin/pg_dump/t/002_pg_dump.pl+++ b/src/bin/pg_dump/t/002_pg_dump.pl@@ -154,6 +154,8 @@ my %pgdump_runs = (
test_key => 'defaults',
dump_cmd => [
[ 'pg_dump', '-Fc', '-Z6', '--no-sync', 'postgres', ],
+ '|',+ [ 'perl', '-pe', '', ],
'>', "$tempdir/defaults_custom_format_no_seek_parallel_restore.dump", # stdout disables seeking
],
restore_cmd => [
--
2.24.2
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To: pgsql-hackers@postgresql.org
Cc: pryzby@telsasoft.com, davidgilman1@gmail.com, jimw54321@gmail.com
Subject: Re: Warn when parallel restoring a custom dump without data offsets
In-Reply-To: <20200622184048.GX17995@telsasoft.com>
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