From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org |
Subject: | Re: We still claim "cannot begin/end transactions in PL/pgSQL" |
Date: | 2018-05-31 12:01:10 |
Message-ID: | b964bd07-65e2-5949-70dc-974332ad24fd@2ndquadrant.com |
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Lists: | pgsql-hackers |
On 5/25/18 12:16, Tom Lane wrote:
> I notice there are still several places in pl_exec.c like this:
>
> case SPI_ERROR_TRANSACTION:
> ereport(ERROR,
> (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> errmsg("cannot begin/end transactions in PL/pgSQL"),
> errhint("Use a BEGIN block with an EXCEPTION clause instead.")));
> break;
>
> At best, the wording of these error messages is now obsolete. I'm not
> sure if we expect them to be reachable at all. If they should be
> can't-happen cases, I'd suggest just deleting them and letting control
> fall to the generic default: cases in each switch. If they are reachable,
> the messages need work.
There are three occurrences:
The occurrence in exec_prepare_plan() could never be reached AFAICT,
because SPI_prepare_params() does not produce those SPI_prepare_params()
error values in the first place. So remove them altogether.
The occurrence in exec_stmt_execsql() can be reached by running for
example SAVEPOINT, or any other TransactionStmt other than COMMIT and
ROLLBACK, which are intercepted by PL/pgSQL. So we still need an error
message there. Unfortunately, we don't know which TransactionStmt
caused the error, so the error has to be pretty generic.
The occurrence in exec_stmt_dynexecute() can be reached using something
like EXECUTE 'COMMIT', which is not supported/not implemented. Hence a
tweaked error message there as well.
Possible patch attached.
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
Attachment | Content-Type | Size |
---|---|---|
0001-Reword-SPI_ERROR_TRANSACTION-errors-in-PL-pgSQL.patch | text/plain | 2.5 KB |
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