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, 7 insertions, 9 deletions

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index c9bded082ec..43b14750351 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -319,7 +319,7 @@ static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
 					   const Oid *excludeOps,
 					   bool attrsOnly, bool showTblSpc,
 					   int prettyFlags, bool missing_ok);
-static char *pg_get_statisticsext_worker(Oid statextid, bool missing_ok);
+static char *pg_get_statisticsobj_worker(Oid statextid, bool missing_ok);
 static char *pg_get_partkeydef_worker(Oid relid, int prettyFlags,
 						 bool attrsOnly, bool missing_ok);
 static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
@@ -1425,16 +1425,16 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
 }
 
 /*
- * pg_get_statisticsextdef
+ * pg_get_statisticsobjdef
  *		Get the definition of an extended statistics object
  */
 Datum
-pg_get_statisticsextdef(PG_FUNCTION_ARGS)
+pg_get_statisticsobjdef(PG_FUNCTION_ARGS)
 {
 	Oid			statextid = PG_GETARG_OID(0);
 	char	   *res;
 
-	res = pg_get_statisticsext_worker(statextid, true);
+	res = pg_get_statisticsobj_worker(statextid, true);
 
 	if (res == NULL)
 		PG_RETURN_NULL();
@@ -1446,7 +1446,7 @@ pg_get_statisticsextdef(PG_FUNCTION_ARGS)
  * Internal workhorse to decompile an extended statistics object.
  */
 static char *
-pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
+pg_get_statisticsobj_worker(Oid statextid, bool missing_ok)
 {
 	Form_pg_statistic_ext	statextrec;
 	HeapTuple	statexttup;
@@ -1467,7 +1467,7 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 	{
 		if (missing_ok)
 			return NULL;
-		elog(ERROR, "cache lookup failed for extended statistics %u", statextid);
+		elog(ERROR, "cache lookup failed for statistics object %u", statextid);
 	}
 
 	statextrec = (Form_pg_statistic_ext) GETSTRUCT(statexttup);
@@ -1480,8 +1480,7 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 												NameStr(statextrec->stxname)));
 
 	/*
-	 * Lookup the stxkind column so that we know how to handle the WITH
-	 * clause.
+	 * Decode the stxkind column so that we know which stats types to print.
 	 */
 	datum = SysCacheGetAttr(STATEXTOID, statexttup,
 							Anum_pg_statistic_ext_stxkind, &isnull);
@@ -1518,7 +1517,6 @@ pg_get_statisticsext_worker(Oid statextid, bool missing_ok)
 			appendStringInfoString(&buf, "ndistinct");
 		else if (dependencies_enabled)
 			appendStringInfoString(&buf, "dependencies");
-
 		appendStringInfoChar(&buf, ')');
 	}