Collection of typo fixes.

Use "a" and "an" correctly, mostly in comments. Two error messages were
also fixed (they were just elogs, so no translation work required). Two
function comments in pg_proc.h were also fixed. Etsuro Fujita reported one
of these, but I found a lot more with grep.

Also fix a few other typos spotted while grepping for the a/an typos.
For example, "consists out of ..." -> "consists of ...". Plus a "though"/
"through" mixup reported by Euler Taveira.

Many of these typos were in old code, which would be nice to backpatch to
make future backpatching easier. But much of the code was new, and I didn't
feel like crafting separate patches for each branch. So no backpatching.

Author: hlinnaka

contrib/isn/isn.c

@@ -511,7 +511,7 @@ str2ean(const char *num)
 }
 
 /*
- * ean2string --- Try to convert an ean13 number to an hyphenated string.
+ * ean2string --- Try to convert an ean13 number to a hyphenated string.
  *				  Assumes there's enough space in result to hold
  *				  the string (maximum MAXEAN13LEN+1 bytes)
  *				  This doesn't verify for a valid check digit.

contrib/pg_buffercache/pg_buffercache_pages.c

@@ -142,7 +142,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
 			LWLockAcquire(BufMappingPartitionLockByIndex(i), LW_SHARED);
 
 		/*
-		 * Scan though all the buffers, saving the relevant fields in the
+		 * Scan through all the buffers, saving the relevant fields in the
 		 * fctx->record structure.
 		 */
 		for (i = 0; i < NBuffers; i++)

contrib/spi/timetravel.c

@@ -51,7 +51,7 @@ static EPlan *find_plan(char *ident, EPlan **eplan, int *nplans);
  *			and all other column values as in new tuple, and insert tuple
  *			with old data and stop_date eq current date
  *			ELSE - skip updation of tuple.
- *		2.  IF an delete affects tuple with stop_date eq INFINITY
+ *		2.  IF a delete affects tuple with stop_date eq INFINITY
  *			then insert the same tuple with stop_date eq current date
  *			[ and delete_user eq current user ]
  *			ELSE - skip deletion of tuple.

contrib/test_decoding/expected/decoding_in_xact.out

@@ -11,7 +11,7 @@ SELECT txid_current() = 0;
 SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
 ERROR:  cannot create logical replication slot in transaction that has performed writes
 ROLLBACK;
--- fail because we're creating a slot while in an subxact whose topxact has a xid
+-- fail because we're creating a slot while in a subxact whose topxact has an xid
 BEGIN;
 SELECT txid_current() = 0;
  ?column? 

contrib/test_decoding/specs/ondisk_startup.spec

@@ -36,7 +36,7 @@ step "s3txid" { BEGIN ISOLATION LEVEL REPEATABLE READ; SELECT txid_current() IS
 step "s3c" { COMMIT; }
 
 # Force usage of ondisk snapshot by starting and not finishing a
-# transaction with a assigned xid after consistency has been
+# transaction with an assigned xid after consistency has been
 # reached. In combination with a checkpoint forcing a snapshot to be
 # written and a new restart point computed that'll lead to the usage
 # of the snapshot.

contrib/test_decoding/sql/decoding_in_xact.sql

@@ -7,7 +7,7 @@ SELECT txid_current() = 0;
 SELECT 'init' FROM pg_create_logical_replication_slot('regression_slot', 'test_decoding');
 ROLLBACK;
 
--- fail because we're creating a slot while in an subxact whose topxact has a xid
+-- fail because we're creating a slot while in a subxact whose topxact has an xid
 BEGIN;
 SELECT txid_current() = 0;
 SAVEPOINT barf;

doc/src/sgml/ref/insert.sgml

@@ -415,7 +415,7 @@ INSERT INTO <replaceable class="PARAMETER">table_name</replaceable> [ AS <replac
    one or more <replaceable
    class="PARAMETER">column_name_index</replaceable> columns and/or
    <replaceable class="PARAMETER">expression_index</replaceable>
-   expressions, and a optional <replaceable class="PARAMETER">
+   expressions, and an optional <replaceable class="PARAMETER">
    index_predicate</replaceable>.
   </para>
 

src/backend/access/brin/brin_pageops.c

@@ -492,7 +492,7 @@ brin_evacuate_page(Relation idxRel, BlockNumber pagesPerRange,
 /*
  * Return a pinned and exclusively locked buffer which can be used to insert an
  * index item of size itemsz.  If oldbuf is a valid buffer, it is also locked
- * (in a order determined to avoid deadlocks.)
+ * (in an order determined to avoid deadlocks.)
  *
  * If there's no existing page with enough free space to accomodate the new
  * item, the relation is extended.  If this happens, *extended is set to true.

src/backend/access/gin/ginbtree.c

@@ -313,7 +313,7 @@ ginFindParents(GinBtree btree, GinBtreeStack *stack)
  * the parent needs to be updated. (a root split returns true as it doesn't
  * need any further action by the caller to complete)
  *
- * When inserting a downlink to a internal page, 'childbuf' contains the
+ * When inserting a downlink to an internal page, 'childbuf' contains the
  * child page that was split. Its GIN_INCOMPLETE_SPLIT flag will be cleared
  * atomically with the insert. Also, the existing item at the given location
  * is updated to point to 'updateblkno'.

src/backend/access/gin/ginxlog.c

@@ -409,7 +409,7 @@ ginRedoSplit(XLogReaderState *record)
 
 /*
  * VACUUM_PAGE record contains simply a full image of the page, similar to
- * a XLOG_FPI record.
+ * an XLOG_FPI record.
  */
 static void
 ginRedoVacuumPage(XLogReaderState *record)

src/backend/access/heap/heapam.c

@@ -5107,7 +5107,7 @@ compute_new_xmax_infomask(TransactionId xmax, uint16 old_infomask,
 /*
  * Subroutine for heap_lock_updated_tuple_rec.
  *
- * Given an hypothetical multixact status held by the transaction identified
+ * Given a hypothetical multixact status held by the transaction identified
  * with the given xid, does the current transaction need to wait, fail, or can
  * it continue if it wanted to acquire a lock of the given mode?  "needwait"
  * is set to true if waiting is necessary; if it can continue, then
@@ -7139,7 +7139,7 @@ log_heap_update(Relation reln, Buffer oldbuf,
 }
 
 /*
- * Perform XLogInsert of a XLOG_HEAP2_NEW_CID record
+ * Perform XLogInsert of an XLOG_HEAP2_NEW_CID record
  *
  * This is only used in wal_level >= WAL_LEVEL_LOGICAL, and only for catalog
  * tuples.
@@ -7179,7 +7179,7 @@ log_heap_new_cid(Relation relation, HeapTuple tup)
 		 *
 		 * We need to check for LOCK ONLY because multixacts might be
 		 * transferred to the new tuple in case of FOR KEY SHARE updates in
-		 * which case there will be a xmax, although the tuple just got
+		 * which case there will be an xmax, although the tuple just got
 		 * inserted.
 		 */
 		if (hdr->t_infomask & HEAP_XMAX_INVALID ||
@@ -7217,7 +7217,7 @@ log_heap_new_cid(Relation relation, HeapTuple tup)
  * Build a heap tuple representing the configured REPLICA IDENTITY to represent
  * the old tuple in a UPDATE or DELETE.
  *
- * Returns NULL if there's no need to log a identity or if there's no suitable
+ * Returns NULL if there's no need to log an identity or if there's no suitable
  * key in the Relation relation.
  */
 static HeapTuple

src/backend/access/heap/rewriteheap.c

@@ -195,7 +195,7 @@ typedef struct
 typedef OldToNewMappingData *OldToNewMapping;
 
 /*
- * In-Memory data for a xid that might need logical remapping entries
+ * In-Memory data for an xid that might need logical remapping entries
  * to be logged.
  */
 typedef struct RewriteMappingFile

src/backend/access/nbtree/nbtsearch.c

@@ -118,7 +118,7 @@ _bt_search(Relation rel, int keysz, ScanKey scankey, bool nextkey,
 		 * In write-mode, allow _bt_moveright to finish any incomplete splits
 		 * along the way.  Strictly speaking, we'd only need to finish an
 		 * incomplete split on the leaf page we're about to insert to, not on
-		 * any of the upper levels (they is taken care of in _bt_getstackbuf,
+		 * any of the upper levels (they are taken care of in _bt_getstackbuf,
 		 * if the leaf page is split and we insert to the parent page).  But
 		 * this is a good opportunity to finish splits of internal pages too.
 		 */

src/backend/access/rmgrdesc/xactdesc.c

@@ -21,7 +21,7 @@
 #include "utils/timestamp.h"
 
 /*
- * Parse the WAL format of a xact commit and abort records into a easier to
+ * Parse the WAL format of an xact commit and abort records into an easier to
  * understand format.
  *
  * This routines are in xactdesc.c because they're accessed in backend (when

src/backend/access/transam/commit_ts.c

@@ -122,7 +122,7 @@ static void WriteSetTimestampXlogRec(TransactionId mainxid, int nsubxids,
  * subtrans implementation changes in the future, we might want to revisit the
  * decision of storing timestamp info for each subxid.
  *
- * The do_xlog parameter tells us whether to include a XLog record of this
+ * The do_xlog parameter tells us whether to include an XLog record of this
  * or not.  Normal path through RecordTransactionCommit() will be related
  * to a transaction commit XLog record, and so should pass "false" here.
  * Other callers probably want to pass true, so that the given values persist

src/backend/access/transam/xact.c

@@ -221,7 +221,7 @@ static TransactionStateData TopTransactionStateData = {
 
 /*
  * unreportedXids holds XIDs of all subtransactions that have not yet been
- * reported in a XLOG_XACT_ASSIGNMENT record.
+ * reported in an XLOG_XACT_ASSIGNMENT record.
  */
 static int	nUnreportedXids;
 static TransactionId unreportedXids[PGPROC_MAX_CACHED_SUBXIDS];
@@ -532,7 +532,7 @@ AssignTransactionId(TransactionState s)
 	/*
 	 * When wal_level=logical, guarantee that a subtransaction's xid can only
 	 * be seen in the WAL stream if its toplevel xid has been logged before.
-	 * If necessary we log a xact_assignment record with fewer than
+	 * If necessary we log an xact_assignment record with fewer than
 	 * PGPROC_MAX_CACHED_SUBXIDS. Note that it is fine if didLogXid isn't set
 	 * for a transaction even though it appears in a WAL record, we just might
 	 * superfluously log something. That can happen when an xid is included
@@ -1232,8 +1232,8 @@ RecordTransactionCommit(void)
 	 * Check if we want to commit asynchronously.  We can allow the XLOG flush
 	 * to happen asynchronously if synchronous_commit=off, or if the current
 	 * transaction has not performed any WAL-logged operation or didn't assign
-	 * a xid.  The transaction can end up not writing any WAL, even if it has
-	 * a xid, if it only wrote to temporary and/or unlogged tables.  It can
+	 * an xid.  The transaction can end up not writing any WAL, even if it has
+	 * an xid, if it only wrote to temporary and/or unlogged tables.  It can
 	 * end up having written WAL without an xid if it did HOT pruning.  In
 	 * case of a crash, the loss of such a transaction will be irrelevant;
 	 * temp tables will be lost anyway, unlogged tables will be truncated and
@@ -1305,7 +1305,7 @@ RecordTransactionCommit(void)
 	/*
 	 * Wait for synchronous replication, if required. Similar to the decision
 	 * above about using committing asynchronously we only want to wait if
-	 * this backend assigned a xid and wrote WAL.  No need to wait if a xid
+	 * this backend assigned an xid and wrote WAL.  No need to wait if an xid
 	 * was assigned due to temporary/unlogged tables or due to HOT pruning.
 	 *
 	 * Note that at this stage we have marked clog, but still show as running

src/backend/access/transam/xlog.c

@@ -8832,7 +8832,7 @@ CreateRestartPoint(int flags)
 	}
 
 	/*
-	 * Due to an historical accident multixact truncations are not WAL-logged,
+	 * Due to a historical accident multixact truncations are not WAL-logged,
 	 * but just performed everytime the mxact horizon is increased. So, unless
 	 * we explicitly execute truncations on a standby it will never clean out
 	 * /pg_multixact which obviously is bad, both because it uses space and

src/backend/catalog/catalog.c

@@ -117,7 +117,7 @@ IsCatalogClass(Oid relid, Form_pg_class reltuple)
 	 * We could instead check whether the relation is pinned in pg_depend, but
 	 * this is noticeably cheaper and doesn't require catalog access.
 	 *
-	 * This test is safe since even a oid wraparound will preserve this
+	 * This test is safe since even an oid wraparound will preserve this
 	 * property (c.f. GetNewObjectId()) and it has the advantage that it works
 	 * correctly even if a user decides to create a relation in the pg_catalog
 	 * namespace.

src/backend/catalog/storage.c

@@ -119,7 +119,7 @@ RelationCreateStorage(RelFileNode rnode, char relpersistence)
 }
 
 /*
- * Perform XLogInsert of a XLOG_SMGR_CREATE record to WAL.
+ * Perform XLogInsert of an XLOG_SMGR_CREATE record to WAL.
  */
 void
 log_smgrcreate(RelFileNode *rnode, ForkNumber forkNum)

src/backend/commands/copy.c

@@ -3346,7 +3346,7 @@ CopyReadLineText(CopyState cstate)
 			 * just use the char as a toggle. If they are different, we need
 			 * to ensure that we only take account of an escape inside a
 			 * quoted field and immediately preceding a quote char, and not
-			 * the second in a escape-escape sequence.
+			 * the second in an escape-escape sequence.
 			 */
 			if (in_quote && c == escapec)
 				last_was_esc = !last_was_esc;

src/backend/commands/event_trigger.c

@@ -1771,7 +1771,7 @@ EventTriggerCollectAlterTableSubcmd(Node *subcmd, ObjectAddress address)
  * EventTriggerAlterTableEnd
  *		Finish up saving an ALTER TABLE command, and add it to command list.
  *
- * FIXME this API isn't considering the possibility that a xact/subxact is
+ * FIXME this API isn't considering the possibility that an xact/subxact is
  * aborted partway through.  Probably it's best to add an
  * AtEOSubXact_EventTriggers() to fix this.
  */

src/backend/commands/sequence.c

@@ -703,8 +703,8 @@ nextval_internal(Oid relid)
 	/*
 	 * If something needs to be WAL logged, acquire an xid, so this
 	 * transaction's commit will trigger a WAL flush and wait for
-	 * syncrep. It's sufficient to ensure the toplevel transaction has a xid,
-	 * no need to assign xids subxacts, that'll already trigger a appropriate
+	 * syncrep. It's sufficient to ensure the toplevel transaction has an xid,
+	 * no need to assign xids subxacts, that'll already trigger an appropriate
 	 * wait.  (Have to do that here, so we're outside the critical section)
 	 */
 	if (logit && RelationNeedsWAL(seqrel))

src/backend/commands/tablecmds.c

@@ -2342,7 +2342,7 @@ RangeVarCallbackForRenameAttribute(const RangeVar *rv, Oid relid, Oid oldrelid,
 }
 
 /*
- *		renameatt		- changes the name of a attribute in a relation
+ *		renameatt		- changes the name of an attribute in a relation
  *
  * The returned ObjectAddress is that of the renamed column.
  */

src/backend/executor/execIndexing.c

@@ -53,7 +53,7 @@
  * Speculative insertion
  * ---------------------
  *
- * Speculative insertion is a is a two-phase mechanism, used to implement
+ * Speculative insertion is a two-phase mechanism used to implement
  * INSERT ... ON CONFLICT DO UPDATE/NOTHING.  The tuple is first inserted
  * to the heap and update the indexes as usual, but if a constraint is
  * violated, we can still back out the insertion without aborting the whole

src/backend/optimizer/README

@@ -656,7 +656,7 @@ EquivalenceClasses and PathKeys after query_planner has completed.
 In these cases, the extra ECs/PKs are needed to represent sort orders
 that were not considered during query_planner.  Such situations should be
 minimized since it is impossible for query_planner to return a plan
-producing such a sort order, meaning a explicit sort will always be needed.
+producing such a sort order, meaning an explicit sort will always be needed.
 Currently this happens only for queries involving multiple window functions
 with different orderings, for which extra sorts are needed anyway.
 

src/backend/optimizer/path/indxpath.c

@@ -3968,7 +3968,7 @@ prefix_quals(Node *leftop, Oid opfamily, Oid collation,
 }
 
 /*
- * Given a leftop and a rightop, and a inet-family sup/sub operator,
+ * Given a leftop and a rightop, and an inet-family sup/sub operator,
  * generate suitable indexqual condition(s).  expr_op is the original
  * operator, and opfamily is the index opfamily.
  */

src/backend/parser/gram.y

@@ -9484,8 +9484,8 @@ InsertStmt:
 
 /*
  * Can't easily make AS optional here, because VALUES in insert_rest would
- * have a shift/reduce conflict with a values as a optional alias. We could
- * easily allow unreserved_keywords as optional aliases, but that'd be a odd
+ * have a shift/reduce conflict with a values as an optional alias. We could
+ * easily allow unreserved_keywords as optional aliases, but that'd be an odd
  * divergance from other places.  So just require AS for now.
  */
 insert_target:

src/backend/port/atomics.c

@@ -52,7 +52,7 @@ pg_atomic_init_flag_impl(volatile pg_atomic_flag *ptr)
 #ifndef HAVE_SPINLOCKS
 	/*
 	 * NB: If we're using semaphore based TAS emulation, be careful to use a
-	 * separate set of semaphores. Otherwise we'd get in trouble if a atomic
+	 * separate set of semaphores. Otherwise we'd get in trouble if an atomic
 	 * var would be manipulated while spinlock is held.
 	 */
 	s_init_lock_sema((slock_t *) &ptr->sema, true);

src/backend/replication/basebackup.c

@@ -443,7 +443,7 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
 			/*
 			 * Mark file as archived, otherwise files can get archived again
 			 * after promotion of a new node. This is in line with
-			 * walreceiver.c always doing a XLogArchiveForceDone() after a
+			 * walreceiver.c always doing an XLogArchiveForceDone() after a
 			 * complete segment.
 			 */
 			StatusFilePath(pathbuf, walFiles[i], ".done");

src/backend/replication/logical/logical.c

@@ -149,7 +149,7 @@ StartupDecodingContext(List *output_plugin_options,
 	 * replication slots.
 	 *
 	 * We can only do so if we're outside of a transaction (i.e. the case when
-	 * streaming changes via walsender), otherwise a already setup
+	 * streaming changes via walsender), otherwise an already setup
 	 * snapshot/xid would end up being ignored. That's not a particularly
 	 * bothersome restriction since the SQL interface can't be used for
 	 * streaming anyway.
@@ -225,7 +225,7 @@ CreateInitDecodingContext(char *plugin,
 
 	/* first some sanity checks that are unlikely to be violated */
 	if (slot == NULL)
-		elog(ERROR, "cannot perform logical decoding without a acquired slot");
+		elog(ERROR, "cannot perform logical decoding without an acquired slot");
 
 	if (plugin == NULL)
 		elog(ERROR, "cannot initialize logical decoding without a specified plugin");
@@ -377,7 +377,7 @@ CreateDecodingContext(XLogRecPtr start_lsn,
 
 	/* first some sanity checks that are unlikely to be violated */
 	if (slot == NULL)
-		elog(ERROR, "cannot perform logical decoding without a acquired slot");
+		elog(ERROR, "cannot perform logical decoding without an acquired slot");
 
 	/* make sure the passed slot is suitable, these are user facing errors */
 	if (slot->data.database == InvalidOid)
@@ -436,7 +436,7 @@ CreateDecodingContext(XLogRecPtr start_lsn,
 }
 
 /*
- * Returns true if an consistent initial decoding snapshot has been built.
+ * Returns true if a consistent initial decoding snapshot has been built.
  */
 bool
 DecodingContextReady(LogicalDecodingContext *ctx)

src/backend/replication/logical/logicalfuncs.c

@@ -53,7 +53,7 @@ typedef struct DecodingOutputState
 } DecodingOutputState;
 
 /*
- * Prepare for a output plugin write.
+ * Prepare for an output plugin write.
  */
 static void
 LogicalOutputPrepareWrite(LogicalDecodingContext *ctx, XLogRecPtr lsn, TransactionId xid,