Fix inconsistencies and typos in the tree

This is numbered take 7, and addresses a set of issues with code
comments, variable names and unreferenced variables.

Author: Alexander Lakhin
Discussion: https://postgr.es/m/dff75442-2468-f74f-568c-6006e141062f@gmail.com

src/backend/access/common/reloptions.c

@@ -69,7 +69,7 @@
  * currently executing.
  *
  * Fillfactor can be set because it applies only to subsequent changes made to
- * data blocks, as documented in heapio.c
+ * data blocks, as documented in hio.c
  *
  * n_distinct options can be set at ShareUpdateExclusiveLock because they
  * are only used during ANALYZE, which uses a ShareUpdateExclusiveLock,

src/backend/access/gin/gindatapage.c

@@ -92,7 +92,7 @@ typedef struct
 
 	/*
 	 * The following fields represent the items in this segment. If 'items' is
-	 * not NULL, it contains a palloc'd array of the itemsin this segment. If
+	 * not NULL, it contains a palloc'd array of the items in this segment. If
 	 * 'seg' is not NULL, it contains the items in an already-compressed
 	 * format. It can point to an on-disk page (!modified), or a palloc'd
 	 * segment in memory. If both are set, they must represent the same items.

src/backend/access/gist/gistget.c

@@ -663,7 +663,7 @@ gistgettuple(IndexScanDesc scan, ScanDirection dir)
 			}
 
 			/*
-			 * Check the last returned tuple and add it to killitems if
+			 * Check the last returned tuple and add it to killedItems if
 			 * necessary
 			 */
 			if (scan->kill_prior_tuple

src/backend/access/gist/gistutil.c

@@ -120,7 +120,7 @@ gistjoinvector(IndexTuple *itvec, int *len, IndexTuple *additvec, int addlen)
 }
 
 /*
- * make plain IndexTupleVector
+ * make plain IndexTuple vector
  */
 
 IndexTupleData *

src/backend/access/hash/hashovfl.c

@@ -793,7 +793,7 @@ _hash_initbitmapbuffer(Buffer buf, uint16 bmsize, bool initpage)
  *	be confused into returning the same tuple more than once or some tuples
  *	not at all by the rearrangement we are performing here.  To prevent
  *	any concurrent scan to cross the squeeze scan we use lock chaining
- *	similar to hasbucketcleanup.  Refer comments atop hashbucketcleanup.
+ *	similar to hashbucketcleanup.  Refer comments atop hashbucketcleanup.
  *
  *	We need to retain a pin on the primary bucket to ensure that no concurrent
  *	split can start.

src/backend/access/hash/hashpage.c

@@ -509,7 +509,7 @@ _hash_init_metabuffer(Buffer buf, double num_tuples, RegProcedure procid,
 	 * Choose the number of initial bucket pages to match the fill factor
 	 * given the estimated number of tuples.  We round up the result to the
 	 * total number of buckets which has to be allocated before using its
-	 * _hashm_spare element. However always force at least 2 bucket pages. The
+	 * hashm_spares element. However always force at least 2 bucket pages. The
 	 * upper limit is determined by considerations explained in
 	 * _hash_expandtable().
 	 */

src/backend/access/heap/heapam.c

@@ -102,7 +102,7 @@ static void MultiXactIdWait(MultiXactId multi, MultiXactStatus status, uint16 in
 static bool ConditionalMultiXactIdWait(MultiXactId multi, MultiXactStatus status,
 									   uint16 infomask, Relation rel, int *remaining);
 static XLogRecPtr log_heap_new_cid(Relation relation, HeapTuple tup);
-static HeapTuple ExtractReplicaIdentity(Relation rel, HeapTuple tup, bool key_modified,
+static HeapTuple ExtractReplicaIdentity(Relation rel, HeapTuple tup, bool key_changed,
 										bool *copy);
 
 

src/backend/access/heap/pruneheap.c

@@ -256,7 +256,7 @@ heap_page_prune(Relation relation, Buffer buffer, TransactionId OldestXmin,
 		MarkBufferDirty(buffer);
 
 		/*
-		 * Emit a WAL HEAP_CLEAN record showing what we did
+		 * Emit a WAL XLOG_HEAP2_CLEAN record showing what we did
 		 */
 		if (RelationNeedsWAL(relation))
 		{

src/backend/access/index/genam.c

@@ -557,8 +557,8 @@ systable_endscan(SysScanDesc sysscan)
  * we could do a heapscan and sort, but the uses are in places that
  * probably don't need to still work with corrupted catalog indexes.)
  * For the moment, therefore, these functions are merely the thinnest of
- * wrappers around index_beginscan/index_getnext.  The main reason for their
- * existence is to centralize possible future support of lossy operators
+ * wrappers around index_beginscan/index_getnext_slot.  The main reason for
+ * their existence is to centralize possible future support of lossy operators
  * in catalog scans.
  */
 SysScanDesc

src/backend/access/spgist/spgscan.c

@@ -643,7 +643,7 @@ spgInnerTest(SpGistScanOpaque so, SpGistSearchItem *item,
 				continue;
 
 			/*
-			 * Use infinity distances if innerConsistent() failed to return
+			 * Use infinity distances if innerConsistentFn() failed to return
 			 * them or if is a NULL item (their distances are really unused).
 			 */
 			distances = out.distances ? out.distances[i] : so->infDistances;

src/backend/access/transam/clog.c

@@ -891,7 +891,7 @@ ExtendCLOG(TransactionId newestXact)
  * Remove all CLOG segments before the one holding the passed transaction ID
  *
  * Before removing any CLOG data, we must flush XLOG to disk, to ensure
- * that any recently-emitted HEAP_FREEZE records have reached disk; otherwise
+ * that any recently-emitted FREEZE_PAGE records have reached disk; otherwise
  * a crash and restart might leave us with some unfrozen tuples referencing
  * removed CLOG data.  We choose to emit a special TRUNCATE XLOG record too.
  * Replaying the deletion from XLOG is not critical, since the files could

src/backend/access/transam/xlog.c

@@ -9158,7 +9158,7 @@ CreateRestartPoint(int flags)
 
 	/*
 	 * Update pg_control, using current time.  Check that it still shows
-	 * IN_ARCHIVE_RECOVERY state and an older checkpoint, else do nothing;
+	 * DB_IN_ARCHIVE_RECOVERY state and an older checkpoint, else do nothing;
 	 * this is a quick hack to make sure nothing really bad happens if somehow
 	 * we get here after the end-of-recovery checkpoint.
 	 */