Re: [HACKERS] Make pg_basebackup -x stream the default

Summary

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Thank you for submission! I think it needs a bit more work to be even better.

Please deal with '-x' argument and with wording in documentation.

Submission review

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Patch is in correct format.

Patch applies cleanly on HEAD.

Tests pass. There seems to be sufficient amount of tests to cover a change.

Usability review

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Patch sounds like a good idea and does what it supposed to do. /me in DBA hat will be happy to have it.

However, it makes '-x' parameter a bit confusing/surprising: specifying it will be equivalent to '-X fetch' which is surprising regression from the new default.

I think we need to either change -x to be equivalent to '-X streaming' or just get rid of it altogether.

Feature test

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I've tested the change manually by doing pg_basebackup with -X none, -X streaming and -X fetch and their shorthand variants, each with max_wal_senders sent to 1 and 2.

I've got all the expected results/failures (e.g. -X streaming fails when max_wal_senders set to 1).

Regression tests pass.

Coding review

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One comment about docs:

         Includes the required transaction log files (WAL files) in the

         backup. This will include all transaction logs generated during

-        the backup. If this option is specified, it is possible to start

-        a postmaster directly in the extracted directory without the need

-        to consult the log archive, thus making this a completely standalone

-        backup.

+        the backup. Unless the option <literal>none</literal> is specified,

+        it is possible to start a postmaster directly in the extracted

+        directory without the need to consult the log archive, thus

+        making this a completely standalone backup.

        </para>

        <para>