Horton

Re: BUG #17434: CREATE/DROP DATABASE can be executed in the same transaction with other commands

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>, Yugo Nagata <nagata@sraoss.co.jp>, PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Date: 2022-07-26T16:03:06Z
Lists: pgsql-bugs, pgsql-hackers 
"David G. Johnston" <david.g.johnston@gmail.com> writes:
> That leaves us with changing the documentation then, from:
> CREATE DATABASE cannot be executed inside a transaction block.
> to:
> CREATE DATABASE cannot be executed inside an explicit transaction block (it
> will error in this case), and will commit (or rollback on failure) any
> implicit transaction it is a part of.

That's not going to help anybody unless we also provide a definition of
"implicit transaction", which is a bit far afield for that man page.

I did miss a bet in the proposed pipeline addendum, though.
I should have written

    ... However, there
    are a few DDL commands (such as <command>CREATE DATABASE</command>)
    that cannot be executed inside a transaction block.  If one of
    these is executed in a pipeline, it will, upon success, force an
    immediate commit to preserve database consistency.

That ties the info to our standard wording in the per-command man
pages.

			regards, tom lane

Commits

  1. Rethink handling of [Prevent|Is]InTransactionBlock in pipeline mode.

  2. Doc: add comments about PreventInTransactionBlock/IsInTransactionBlock.

  3. Force immediate commit after CREATE DATABASE etc in extended protocol.