Fix misc typos.

Oskari Saarenmaa. Backpatch to stable branches where applicable.

src/backend/access/brin/brin_revmap.c

@@ -127,7 +127,7 @@ brinRevmapExtend(BrinRevmap *revmap, BlockNumber heapBlk)
  * it's not long enough.
  *
  * The returned buffer is also recorded in the revmap struct; finishing that
- * releases the buffer, therefore the caller needn't do it explicitely.
+ * releases the buffer, therefore the caller needn't do it explicitly.
  */
 Buffer
 brinLockRevmapPageForUpdate(BrinRevmap *revmap, BlockNumber heapBlk)
@@ -314,7 +314,7 @@ revmap_get_blkno(BrinRevmap *revmap, BlockNumber heapBlk)
  * Obtain and return a buffer containing the revmap page for the given heap
  * page.  The revmap must have been previously extended to cover that page.
  * The returned buffer is also recorded in the revmap struct; finishing that
- * releases the buffer, therefore the caller needn't do it explicitely.
+ * releases the buffer, therefore the caller needn't do it explicitly.
  */
 static Buffer
 revmap_get_buffer(BrinRevmap *revmap, BlockNumber heapBlk)

src/backend/access/common/heaptuple.c

@@ -805,7 +805,7 @@ heap_modify_tuple(HeapTuple tuple,
 	 * repl information, as appropriate.
 	 *
 	 * NOTE: it's debatable whether to use heap_deform_tuple() here or just
-	 * heap_getattr() only the non-replaced colums.  The latter could win if
+	 * heap_getattr() only the non-replaced columns.  The latter could win if
 	 * there are many replaced columns and few non-replaced ones. However,
 	 * heap_deform_tuple costs only O(N) while the heap_getattr way would cost
 	 * O(N^2) if there are many non-replaced columns, so it seems better to

src/backend/access/gin/ginfast.c

@@ -888,8 +888,8 @@ ginInsertCleanup(GinState *ginstate,
 												 * locking */
 
 			/*
-			 * remove readed pages from pending list, at this point all
-			 * content of readed pages is in regular structure
+			 * remove read pages from pending list, at this point all
+			 * content of read pages is in regular structure
 			 */
 			if (shiftList(index, metabuffer, blkno, stats))
 			{

src/backend/access/gist/gistproc.c

@@ -588,7 +588,7 @@ gist_box_picksplit(PG_FUNCTION_ARGS)
 		 * We first consider splits where b is the lower bound of an entry.
 		 * We iterate through all entries, and for each b, calculate the
 		 * smallest possible a. Then we consider splits where a is the
-		 * uppper bound of an entry, and for each a, calculate the greatest
+		 * upper bound of an entry, and for each a, calculate the greatest
 		 * possible b.
 		 *
 		 * In the above example, the first loop would consider splits:
@@ -638,7 +638,7 @@ gist_box_picksplit(PG_FUNCTION_ARGS)
 		}
 
 		/*
-		 * Iterate over upper bound of left group finding greates possible
+		 * Iterate over upper bound of left group finding greatest possible
 		 * lower bound of right group.
 		 */
 		i1 = nentries - 1;

src/backend/access/heap/heapam.c

@@ -5473,7 +5473,7 @@ l4:
  *
  * The initial tuple is assumed to be already locked.
  *
- * This function doesn't check visibility, it just inconditionally marks the
+ * This function doesn't check visibility, it just unconditionally marks the
  * tuple(s) as locked.  If any tuple in the updated chain is being deleted
  * concurrently (or updated with the key being modified), sleep until the
  * transaction doing it is finished.
@@ -6187,7 +6187,7 @@ heap_prepare_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
 			/*
 			 * NB -- some of these transformations are only valid because we
 			 * know the return Xid is a tuple updater (i.e. not merely a
-			 * locker.) Also note that the only reason we don't explicitely
+			 * locker.) Also note that the only reason we don't explicitly
 			 * worry about HEAP_KEYS_UPDATED is because it lives in
 			 * t_infomask2 rather than t_infomask.
 			 */

src/backend/access/heap/rewriteheap.c

@@ -763,9 +763,9 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
  *
  * Crash-Safety: This module diverts from the usual patterns of doing WAL
  * since it cannot rely on checkpoint flushing out all buffers and thus
- * waiting for exlusive locks on buffers. Usually the XLogInsert() covering
+ * waiting for exclusive locks on buffers. Usually the XLogInsert() covering
  * buffer modifications is performed while the buffer(s) that are being
- * modified are exlusively locked guaranteeing that both the WAL record and
+ * modified are exclusively locked guaranteeing that both the WAL record and
  * the modified heap are on either side of the checkpoint. But since the
  * mapping files we log aren't in shared_buffers that interlock doesn't work.
  *

src/backend/access/transam/xact.c

@@ -83,7 +83,7 @@ int			synchronous_commit = SYNCHRONOUS_COMMIT_ON;
  * When running as a parallel worker, we place only a single
  * TransactionStateData on the parallel worker's state stack, and the XID
  * reflected there will be that of the *innermost* currently-active
- * subtransaction in the backend that initiated paralllelism.  However,
+ * subtransaction in the backend that initiated parallelism.  However,
  * GetTopTransactionId() and TransactionIdIsCurrentTransactionId()
  * need to return the same answers in the parallel worker as they would have
  * in the user backend, so we need some additional bookkeeping.