Remove the query_id_squash_values GUC

Commit 62d712ecfd94 introduced the capability to calculate the same
queryId for queries with different lengths of constants in a list for an
IN clause.  This behavior was originally enabled with a GUC
query_id_squash_values.  After a discussion about the value of such a
GUC, it was decided to back out of the use of a GUC and make the
squashing behavior the only available option.

Author: Sami Imseih <samimseih@gmail.com>
Discussion: https://postgr.es/m/Z-LZyygkkNyA8-kR@msg.df7cb.de
Discussion: https://postgr.es/m/CA+q6zcVTK-3C-8NWV1oY2NZrvtnMCDqnyYYyk1T7WMUG65MeOQ@mail.gmail.com

2 files changed, 2 insertions, 34 deletions

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index f86135fbe1d..65ab95be370 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -8726,36 +8726,6 @@ COPY postgres_log FROM '/full/path/to/logfile.csv' WITH csv;
       </listitem>
      </varlistentry>
 
-     <varlistentry id="guc-query-id-squash-values" xreflabel="query_id_squash_values">
-      <term><varname>query_id_squash_values</varname> (<type>bool</type>)
-      <indexterm>
-       <primary><varname>query_id_squash_values</varname> configuration parameter</primary>
-      </indexterm>
-      </term>
-      <listitem>
-       <para>
-        Specifies how a list of constants (e.g., for an <literal>IN</literal>
-        clause) contributes to the query identifier computation.
-        Normally, every element of such a list contributes to the query
-        identifier separately, which means that two queries that only differ
-        in the number of elements in such a list would get different query
-        identifiers.
-        If this parameter is on, a list of constants will not contribute
-        to the query identifier. This means that two queries whose only
-        difference is the number of constants in such a list are going to get the
-        same query identifier.
-       </para>
-       <para>
-        Only constants are affected; bind parameters do not benefit from this
-        functionality. The default value is <literal>off</literal>.
-       </para>
-       <para>
-        This parameter also affects how <xref linkend="pgstatstatements"/>
-        generates normalized query texts.
-       </para>
-      </listitem>
-     </varlistentry>
-
      <varlistentry id="guc-log-statement-stats">
       <term><varname>log_statement_stats</varname> (<type>boolean</type>)
       <indexterm>
diff --git a/doc/src/sgml/pgstatstatements.sgml b/doc/src/sgml/pgstatstatements.sgml
index 625b84ebfef..7baa07dcdbf 100644
--- a/doc/src/sgml/pgstatstatements.sgml
+++ b/doc/src/sgml/pgstatstatements.sgml
@@ -632,13 +632,11 @@
    In some cases, queries with visibly different texts might get merged into a
    single <structname>pg_stat_statements</structname> entry; as explained above,
    this is expected to happen for semantically equivalent queries.
-   In addition, if <varname>query_id_squash_values</varname> is enabled
-   and the only difference between queries is the number of elements in a list
-   of constants, the list will get squashed down to a single element but shown
+   In addition, if the only difference between queries is the number of elements
+   in a list of constants, the list will get squashed down to a single element but shown
    with a commented-out list indicator:
 
 <screen>
-=# SET query_id_squash_values = on;
 =# SELECT pg_stat_statements_reset();
 =# SELECT * FROM test WHERE a IN (1, 2, 3, 4, 5, 6, 7);
 =# SELECT * FROM test WHERE a IN (1, 2, 3, 4, 5, 6, 7, 8);