Change CREATE STATISTICS syntax

Previously, we had the WITH clause in the middle of the command, where
you'd specify both generic options as well as statistic types.  Few
people liked this, so this commit changes it to remove the WITH keyword
from that clause and makes it accept statistic types only.  (We
currently don't have any generic options, but if we invent in the
future, we will gain a new WITH clause, probably at the end of the
command).

Also, the column list is now specified without parens, which makes the
whole command look more similar to a SELECT command.  This change will
let us expand the command to supporting expressions (not just columns
names) as well as multiple tables and their join conditions.

Tom added lots of code comments and fixed some parts of the CREATE
STATISTICS reference page, too; more changes in this area are
forthcoming.  He also fixed a potential problem in the alter_generic
regression test, reducing verbosity on a cascaded drop to avoid
dependency on message ordering, as we do in other tests.

Tom also closed a security bug: we documented that table ownership was
required in order to create a statistics object on it, but didn't
actually implement it.

Implement tab-completion for statistics objects.  This can stand some
more improvement.

Authors: Alvaro Herrera, with lots of cleanup by Tom Lane
Discussion: https://postgr.es/m/20170420212426.ltvgyhnefvhixm6i@alvherre.pgsql

1 files changed, 5 insertions, 5 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index cbde1fff01c..983b9800ccd 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -1504,15 +1504,15 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 	}
 
 	/*
-	 * If any option is disabled, then we'll need to append a WITH clause to
-	 * show which options are enabled.  We omit the WITH clause on purpose
+	 * If any option is disabled, then we'll need to append the types clause
+	 * to show which options are enabled.  We omit the types clause on purpose
 	 * when all options are enabled, so a pg_dump/pg_restore will create all
 	 * statistics types on a newer postgres version, if the statistics had all
 	 * options enabled on the original version.
 	 */
 	if (!ndistinct_enabled || !dependencies_enabled)
 	{
-		appendStringInfoString(&buf, " WITH (");
+		appendStringInfoString(&buf, " (");
 		if (ndistinct_enabled)
 			appendStringInfoString(&buf, "ndistinct");
 		else if (dependencies_enabled)
@@ -1521,7 +1521,7 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 		appendStringInfoChar(&buf, ')');
 	}
 
-	appendStringInfoString(&buf, " ON (");
+	appendStringInfoString(&buf, " ON ");
 
 	for (colno = 0; colno < statextrec->stxkeys.dim1; colno++)
 	{
@@ -1536,7 +1536,7 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 		appendStringInfoString(&buf, quote_identifier(attname));
 	}
 
-	appendStringInfo(&buf, ") FROM %s",
+	appendStringInfo(&buf, " FROM %s",
 					 generate_relation_name(statextrec->stxrelid, NIL));
 
 	ReleaseSysCache(statexttup);