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Message-ID: <13663265-cac2-ec5d-d378-0dd44a895f8e@gmail.com>
Date: Sat, 11 Nov 2023 16:00:00 +0300
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Subject: Re: pg_basebackup check vs Windows file path limits
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To: Andrew Dunstan <andrew@dunslane.net>, Daniel Gustafsson <daniel@yesql.se>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
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From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <de60e1b0-e2c9-c61a-c65d-c5b288348fa2@dunslane.net>
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Hello Andrew,

08.07.2023 18:52, Andrew Dunstan wrote:
>> Since this test is passing on HEAD which has slightly shorter paths, I'm wondering if we should change this:
>>
>>     rename("$pgdata/pg_replslot", "$tempdir/pg_replslot")
>>       or BAIL_OUT "could not move $pgdata/pg_replslot";
>>     dir_symlink("$tempdir/pg_replslot", "$pgdata/pg_replslot")
>>       or BAIL_OUT "could not symlink to $pgdata/pg_replslot";
>>
>> to use the much shorter $sys_tempdir created a few lines below.
>>
> Pushed a tested fix along those lines.
>

Today I've started up my Windows VM to run some tests and discovered a test
failure caused by that fix (e213de8e7):
 >meson test
Ok:                 246
Expected Fail:      0
Fail:               1
Unexpected Pass:    0
Skipped:            14
Timeout:            0

...\010_pg_basebackup\log\regress_log_010_pg_basebackup.txt contains:
[04:42:45.321](0.291s) Bail out!  could not move 
T:\postgresql\build/testrun/pg_basebackup/010_pg_basebackup\data/t_010_pg_basebackup_main_data/pgdata/pg_replslot

With a diagnostic print added before rename() in 010_pg_basebackup.pl, I see:
rename("T:\postgresql\build/testrun/pg_basebackup/010_pg_basebackup\data/t_010_pg_basebackup_main_data/pgdata/pg_replslot", 
"C:\Users\User\AppData\Local\Temp\fGT76tZUWr/pg_replslot")
That is, I have the postgres source tree and the user tempdir placed on
different disks.

perldoc on rename() says that it usually doesn't work across filesystem
boundaries, so I think it's not a Windows-specific issue.

Best regards,
Alexander
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    <div class="moz-cite-prefix">Hello Andrew,<br>
      <br>
      08.07.2023 18:52, Andrew Dunstan wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:de60e1b0-e2c9-c61a-c65d-c5b288348fa2@dunslane.net">
      <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      <blockquote type="cite"
        cite="mid:8e3130c2-5c51-5cd5-9f0d-b0cd938bcd6b@dunslane.net">
        <pre>
Since this test is passing on HEAD which has slightly shorter paths, I'm wondering if we should change this:
</pre>
        <blockquote>rename("$pgdata/pg_replslot",
          "$tempdir/pg_replslot")<br>
            or BAIL_OUT "could not move $pgdata/pg_replslot";<br>
          dir_symlink("$tempdir/pg_replslot", "$pgdata/pg_replslot")<br>
            or BAIL_OUT "could not symlink to $pgdata/pg_replslot";<br>
        </blockquote>
        <p>to use the much shorter $sys_tempdir created a few lines
          below.</p>
      </blockquote>
      <p>Pushed a tested fix along those lines.</p>
    </blockquote>
    <br>
    Today I've started up my Windows VM to run some tests and discovered
    a test<br>
    failure caused by that fix (e213de8e7):<br>
    &gt;meson test<br>
    Ok:                 246<br>
    Expected Fail:      0<br>
    Fail:               1<br>
    Unexpected Pass:    0<br>
    Skipped:            14<br>
    Timeout:            0<br>
    <br>
    ...\010_pg_basebackup\log\regress_log_010_pg_basebackup.txt
    contains:<br>
    [04:42:45.321](0.291s) Bail out!  could not move
T:\postgresql\build/testrun/pg_basebackup/010_pg_basebackup\data/t_010_pg_basebackup_main_data/pgdata/pg_replslot<br>
    <br>
    With a diagnostic print added before rename() in
    010_pg_basebackup.pl, I see:<br>
rename("T:\postgresql\build/testrun/pg_basebackup/010_pg_basebackup\data/t_010_pg_basebackup_main_data/pgdata/pg_replslot",
    "C:\Users\User\AppData\Local\Temp\fGT76tZUWr/pg_replslot")<br>
    That is, I have the postgres source tree and the user tempdir placed
    on<br>
    different disks.<br>
    <br>
    perldoc on rename() says that it usually doesn't work across
    filesystem<br>
    boundaries, so I think it's not a Windows-specific issue.<br>
    <br>
    Best regards,<br>
    Alexander<br>
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