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 <[email protected]>
Discussion: https://postgr.es/m/[email protected]
Discussion: https://postgr.es/m/CA+q6zcVTK-3C-8NWV1oY2NZrvtnMCDqnyYYyk1T7WMUG65MeOQ@mail.gmail.com

5 files changed, 5 insertions, 26 deletions

diff --git a/src/backend/nodes/queryjumblefuncs.c b/src/backend/nodes/queryjumblefuncs.c
index 1d9abd89028..513cf92d357 100644
--- a/src/backend/nodes/queryjumblefuncs.c
+++ b/src/backend/nodes/queryjumblefuncs.c
@@ -46,9 +46,6 @@
 /* GUC parameters */
 int			compute_query_id = COMPUTE_QUERY_ID_AUTO;
 
-/* Whether to merge constants in a list when computing query_id */
-bool		query_id_squash_values = false;
-
 /*
  * True when compute_query_id is ON or AUTO, and a module requests them.
  *
@@ -472,7 +469,7 @@ IsSquashableConstList(List *elements, Node **firstExpr, Node **lastExpr)
 	 * If squashing is disabled, or the list is too short, we don't try to
 	 * squash it.
 	 */
-	if (!query_id_squash_values || list_length(elements) < 2)
+	if (list_length(elements) < 2)
 		return false;
 
 	foreach(temp, elements)
@@ -520,13 +517,10 @@ do { \
 #include "queryjumblefuncs.funcs.c"
 
 /*
- * When query_id_squash_values is enabled, we jumble lists of constant
- * elements as one individual item regardless of how many elements are
- * in the list.  This means different queries jumble to the same query_id,
- * if the only difference is the number of elements in the list.
- *
- * If query_id_squash_values is disabled or the list is not "simple
- * enough", we jumble each element normally.
+ * We jumble lists of constant elements as one individual item regardless
+ * of how many elements are in the list.  This means different queries
+ * jumble to the same query_id, if the only difference is the number of
+ * elements in the list.
  */
 static void
 _jumbleElements(JumbleState *jstate, List *elements)
diff --git a/src/backend/postmaster/launch_backend.c b/src/backend/postmaster/launch_backend.c
index 9e6c900d146..bf6b55ee830 100644
--- a/src/backend/postmaster/launch_backend.c
+++ b/src/backend/postmaster/launch_backend.c
@@ -116,7 +116,6 @@ typedef struct
 	bool		redirection_done;
 	bool		IsBinaryUpgrade;
 	bool		query_id_enabled;
-	bool		query_id_squash_values;
 	int			max_safe_fds;
 	int			MaxBackends;
 	int			num_pmchild_slots;
@@ -778,7 +777,6 @@ save_backend_variables(BackendParameters *param,
 	param->redirection_done = redirection_done;
 	param->IsBinaryUpgrade = IsBinaryUpgrade;
 	param->query_id_enabled = query_id_enabled;
-	param->query_id_squash_values = query_id_squash_values;
 	param->max_safe_fds = max_safe_fds;
 
 	param->MaxBackends = MaxBackends;
@@ -1039,7 +1037,6 @@ restore_backend_variables(BackendParameters *param)
 	redirection_done = param->redirection_done;
 	IsBinaryUpgrade = param->IsBinaryUpgrade;
 	query_id_enabled = param->query_id_enabled;
-	query_id_squash_values = param->query_id_squash_values;
 	max_safe_fds = param->max_safe_fds;
 
 	MaxBackends = param->MaxBackends;
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 989825d3a9c..76c7c6bb4b1 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -2123,16 +2123,6 @@ struct config_bool ConfigureNamesBool[] =
 	},
 
 	{
-		{"query_id_squash_values", PGC_USERSET, STATS_MONITORING,
-			gettext_noop("Allows to merge constants in a list when computing "
-						 "query_id."),
-		},
-		&query_id_squash_values,
-		false,
-		NULL, NULL, NULL
-	},
-
-	{
 		{"vacuum_truncate", PGC_USERSET, VACUUM_DEFAULT,
 			gettext_noop("Enables vacuum to truncate empty pages at the end of the table."),
 		},
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 2246ccb85a7..7c12434efa2 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -664,7 +664,6 @@
 # - Monitoring -
 
 #compute_query_id = auto
-#query_id_squash_values = off
 #log_statement_stats = off
 #log_parser_stats = off
 #log_planner_stats = off
diff --git a/src/include/nodes/queryjumble.h b/src/include/nodes/queryjumble.h
index 62794c5a901..da7c7abed2e 100644
--- a/src/include/nodes/queryjumble.h
+++ b/src/include/nodes/queryjumble.h
@@ -86,7 +86,6 @@ extern JumbleState *JumbleQuery(Query *query);
 extern void EnableQueryId(void);
 
 extern PGDLLIMPORT bool query_id_enabled;
-extern PGDLLIMPORT bool query_id_squash_values;
 
 /*
  * Returns whether query identifier computation has been enabled, either