Horton

Re: Bug in documentation: https://www.postgresql.org/docs/current/spi-examples.html

David G. Johnston <david.g.johnston@gmail.com>

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From: "David G. Johnston" <david.g.johnston@gmail.com>
To: Curt Kolovson <ckolovson@gmail.com>
Cc: pgsql-docs@lists.postgresql.org
Date: 2023-07-18T00:26:26Z
Lists: pgsql-docs 
On Mon, Jul 17, 2023 at 4:53 PM Curt Kolovson <ckolovson@gmail.com> wrote:

> The actual results (shown below) are different than shown on this doc
> page. The reason is because the second parameter to the UDF that is
> passed to SPI_exec is the maximum number of rows to return, or 0 for
> no limit. It is not the maximum number of rows to process. In the case
> of "SELECT execq('INSERT INTO a SELECT x + 2 FROM a', 1)", it returned
> 0 rows, but it inserted (processed) 2 rows. This example should be
> corrected.
>
>
> db=# SELECT execq('INSERT INTO a SELECT x + 2 FROM a', 1);
>  execq
> -------
>      2
> (1 row)
>
>
SPI_exec sees "INSERT 0 2" as the command tag from the SQL command you
passed and so 2 is the output of the execq function call.

No INFO messages appear because you did not include a returning clause.
The 1 you passed to the call is immaterial if the query you supply doesn't
produce a result set.

David J.

Commits

  1. Doc: fix out-of-date example of SPI usage.

  2. Fix SPI documentation for new handling of ExecutorRun's count parameter.