Standardize terminology for pg_statistic_ext entries.

Consistently refer to such an entry as a "statistics object", not just
"statistics" or "extended statistics".  Previously we had a mismash of
terms, accompanied by utter confusion as to whether the term was
singular or plural.  That's not only grating (at least to the ear of
a native English speaker) but could be outright misleading, eg in error
messages that seemed to be referring to multiple objects where only one
could be meant.

This commit fixes the code and a lot of comments (though I may have
missed a few).  I also renamed two new SQL functions,
pg_get_statisticsextdef -> pg_get_statisticsobjdef
pg_statistic_ext_is_visible -> pg_statistics_obj_is_visible
to conform better with this terminology.

I have not touched the SGML docs other than fixing those function
names; the docs certainly need work but it seems like a separable task.

Discussion: https://postgr.es/m/22676.1494557205@sss.pgh.pa.us

1 files changed, 9 insertions, 9 deletions

diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
index db5f4278d55..cab54c962c6 100644
--- a/src/backend/commands/statscmds.c
+++ b/src/backend/commands/statscmds.c
@@ -1,7 +1,7 @@
 /*-------------------------------------------------------------------------
  *
  * statscmds.c
- *	  Commands for creating and altering extended statistics
+ *	  Commands for creating and altering extended statistics objects
  *
  * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -64,7 +64,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 	Oid			relid;
 	ObjectAddress parentobject,
 				myself;
-	Datum		types[2];		/* one for each possible type of statistics */
+	Datum		types[2];		/* one for each possible type of statistic */
 	int			ntypes;
 	ArrayType  *stxkind;
 	bool		build_ndistinct;
@@ -80,7 +80,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 	namestrcpy(&stxname, namestr);
 
 	/*
-	 * Deal with the possibility that the named statistics already exist.
+	 * Deal with the possibility that the statistics object already exists.
 	 */
 	if (SearchSysCacheExists2(STATEXTNAMENSP,
 							  NameGetDatum(&stxname),
@@ -90,14 +90,14 @@ CreateStatistics(CreateStatsStmt *stmt)
 		{
 			ereport(NOTICE,
 					(errcode(ERRCODE_DUPLICATE_OBJECT),
-					 errmsg("statistics \"%s\" already exist, skipping",
+					 errmsg("statistics object \"%s\" already exists, skipping",
 							namestr)));
 			return InvalidObjectAddress;
 		}
 
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_OBJECT),
-				 errmsg("statistics \"%s\" already exist", namestr)));
+				 errmsg("statistics object \"%s\" already exists", namestr)));
 	}
 
 	/*
@@ -263,7 +263,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized statistics type \"%s\"",
+					 errmsg("unrecognized statistic type \"%s\"",
 							type)));
 	}
 	/* If no statistic type was specified, build them all. */
@@ -307,7 +307,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 	relation_close(statrel, RowExclusiveLock);
 
 	/*
-	 * Invalidate relcache so that others see the new statistics.
+	 * Invalidate relcache so that others see the new statistics object.
 	 */
 	CacheInvalidateRelcache(rel);
 
@@ -346,7 +346,7 @@ CreateStatistics(CreateStatsStmt *stmt)
 }
 
 /*
- * Guts of statistics deletion.
+ * Guts of statistics object deletion.
  */
 void
 RemoveStatisticsById(Oid statsOid)
@@ -365,7 +365,7 @@ RemoveStatisticsById(Oid statsOid)
 	tup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statsOid));
 
 	if (!HeapTupleIsValid(tup)) /* should not happen */
-		elog(ERROR, "cache lookup failed for statistics %u", statsOid);
+		elog(ERROR, "cache lookup failed for statistics object %u", statsOid);
 
 	statext = (Form_pg_statistic_ext) GETSTRUCT(tup);
 	relid = statext->stxrelid;