Horton

Re: GUC flags

Michael Paquier <michael@paquier.xyz>

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From: Michael Paquier <michael@paquier.xyz>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, peter.eisentraut@enterprisedb.com, pgsql-hackers@lists.postgresql.org, bruce@momjian.us, tgl@sss.pgh.pa.us
Date: 2022-01-06T05:19:08Z
Lists: pgsql-hackers 
On Wed, Jan 05, 2022 at 05:55:17PM -0600, Justin Pryzby wrote:
> pg_settings is currently defined with "SELECT *".  Is it fine to enumerate a
> list of columns instead ?

I'd like to think that this is a better practice when it comes
documenting the columns, but I don't see an actual need for this extra
complication here.

> +	initStringInfo(&ret);
> +	appendStringInfoChar(&ret, '{');
> +
> +	if (flags & GUC_NO_SHOW_ALL)
> +		appendStringInfo(&ret, "NO_SHOW_ALL,");
> +	if (flags & GUC_NO_RESET_ALL)
> +		appendStringInfo(&ret, "NO_RESET_ALL,");
> +	if (flags & GUC_NOT_IN_SAMPLE)
> +		appendStringInfo(&ret, "NOT_IN_SAMPLE,");
> +	if (flags & GUC_EXPLAIN)
> +		appendStringInfo(&ret, "EXPLAIN,");
> +	if (flags & GUC_RUNTIME_COMPUTED)
> +		appendStringInfo(&ret, "RUNTIME_COMPUTED,");
> +
> +	/* Remove trailing comma, if any */
> +	if (ret.len > 1)
> +		ret.data[--ret.len] = '\0';

The way of building the text array is incorrect here.  See
heap_tuple_infomask_flags() in pageinspect as an example with all the
HEAP_* flags.  I think that you should allocate an array of Datums,
use CStringGetTextDatum() to assign each array element, wrapping the
whole with construct_array() to build the final value for the
parameter tuple.
--
Michael

Commits

  1. Add TAP test to automate the equivalent of check_guc, take two

  2. Retire src/backend/utils/misc/check_guc

  3. Add TAP test to automate the equivalent of check_guc

  4. Add PostgreSQL::Test::Cluster::config_data()

  5. Introduce pg_settings_get_flags() to find flags associated to a GUC

  6. Revert changes about warnings/errors for placeholders.

  7. Improve the description of various GUCs