Fix grammatical typos around possessive "its"

Some places spelled it "it's", which is short for "it is".
In passing, fix a couple other nearby grammatical errors.

Author: Jacob Brazeal <jacob.brazeal@gmail.com>
Discussion: https://postgr.es/m/CA+COZaAO8g1KJCV0T48=CkJMjAnnfTGLWOATz+2aCh40c2Nm+g@mail.gmail.com

contrib/amcheck/verify_nbtree.c

@@ -2469,7 +2469,7 @@ bt_child_highkey_check(BtreeCheckState *state,
 				 * So, now we traverse to the right of that cousin page and
 				 * current child level page under consideration still belongs
 				 * to the subtree of target's left sibling.  Thus, we need to
-				 * match child's high key to it's left uncle page high key.
+				 * match child's high key to its left uncle page high key.
 				 * Thankfully we saved it, it's called a "low key" of target
 				 * page.
 				 */

src/backend/access/spgist/spgscan.c

@@ -865,7 +865,7 @@ redirect:
 
 			if (SpGistPageIsLeaf(page))
 			{
-				/* Page is a leaf - that is, all it's tuples are heap items */
+				/* Page is a leaf - that is, all its tuples are heap items */
 				OffsetNumber max = PageGetMaxOffsetNumber(page);
 
 				if (SpGistBlockIsRoot(blkno))

src/backend/replication/logical/reorderbuffer.c

@@ -1663,7 +1663,7 @@ ReorderBufferTruncateTXN(ReorderBuffer *rb, ReorderBufferTXN *txn, bool txn_prep
 		/* Check we're not mixing changes from different transactions. */
 		Assert(change->txn == txn);
 
-		/* remove the change from it's containing list */
+		/* remove the change from its containing list */
 		dlist_delete(&change->node);
 
 		/*

src/backend/replication/logical/worker.c

@@ -4092,7 +4092,7 @@ subscription_change_cb(Datum arg, int cacheid, uint32 hashvalue)
  * subxact_info_write
  *	  Store information about subxacts for a toplevel transaction.
  *
- * For each subxact we store offset of it's first change in the main file.
+ * For each subxact we store offset of its first change in the main file.
  * The file is always over-written as a whole.
  *
  * XXX We should only store subxacts that were not aborted yet.

src/backend/replication/pgoutput/pgoutput.c

@@ -1849,7 +1849,7 @@ pgoutput_stream_stop(struct LogicalDecodingContext *ctx,
 
 /*
  * Notify downstream to discard the streamed transaction (along with all
- * it's subtransactions, if it's a toplevel transaction).
+ * its subtransactions, if it's a toplevel transaction).
  */
 static void
 pgoutput_stream_abort(struct LogicalDecodingContext *ctx,
@@ -1882,7 +1882,7 @@ pgoutput_stream_abort(struct LogicalDecodingContext *ctx,
 
 /*
  * Notify downstream to apply the streamed transaction (along with all
- * it's subtransactions).
+ * its subtransactions).
  */
 static void
 pgoutput_stream_commit(struct LogicalDecodingContext *ctx,

src/backend/storage/lmgr/lock.c

@@ -1323,7 +1323,7 @@ SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc,
 		 * on our own behalf, in which case our group leader isn't changing
 		 * because the group leader for a process can only ever be changed by
 		 * the process itself; or else we are transferring a fast-path lock to
-		 * the main lock table, in which case that process can't change it's
+		 * the main lock table, in which case that process can't change its
 		 * lock group leader without first releasing all of its locks (and in
 		 * particular the one we are currently transferring).
 		 */

src/backend/storage/lmgr/lwlock.c

@@ -60,7 +60,7 @@
  * The attentive reader might have noticed that naively doing the above has a
  * glaring race condition: We try to lock using the atomic operations and
  * notice that we have to wait. Unfortunately by the time we have finished
- * queuing, the former locker very well might have already finished it's
+ * queuing, the former locker very well might have already finished its
  * work. That's problematic because we're now stuck waiting inside the OS.
 
  * To mitigate those races we use a two phased attempt at locking:

src/backend/utils/adt/formatting.c

@@ -5561,7 +5561,7 @@ NUM_numpart_from_char(NUMProc *Np, int id, int input_len)
 		}
 
 		/*
-		 * try read non-locale sign, it's happen only if format is not exact
+		 * try read non-locale sign, which happens only if format is not exact
 		 * and we cannot determine sign position of MI/PL/SG, an example:
 		 *
 		 * FM9.999999MI			   -> 5.01-

src/backend/utils/adt/jsonpath_exec.c

@@ -77,7 +77,7 @@
 #include "utils/timestamp.h"
 
 /*
- * Represents "base object" and it's "id" for .keyvalue() evaluation.
+ * Represents "base object" and its "id" for .keyvalue() evaluation.
  */
 typedef struct JsonBaseObjectInfo
 {

src/backend/utils/adt/tsrank.c

@@ -812,7 +812,7 @@ get_docrep(TSVector txt, QueryRepresentation *qr, int *doclen)
 		qsort(doc, cur, sizeof(DocRepresentation), compareDocR);
 
 		/*
-		 * Join QueryItem per WordEntry and it's position
+		 * Join QueryItem per WordEntry and its position
 		 */
 		storage.pos = doc->pos;
 		storage.data.query.items = palloc(sizeof(QueryItem *) * qr->query->size);

src/backend/utils/sort/tuplesort.c

@@ -202,7 +202,7 @@ struct Tuplesortstate
 	int64		maxSpace;		/* maximum amount of space occupied among sort
 								 * of groups, either in-memory or on-disk */
 	bool		isMaxSpaceDisk; /* true when maxSpace is value for on-disk
-								 * space, false when it's value for in-memory
+								 * space, false when its value for in-memory
 								 * space */
 	TupSortStatus maxSpaceStatus;	/* sort status when maxSpace was reached */
 	LogicalTapeSet *tapeset;	/* logtape.c object for tapes in a temp file */

src/bin/pg_combinebackup/reconstruct.c

@@ -214,7 +214,7 @@ reconstruct_from_incremental_file(char *input_filename,
 			 * taking no action on those blocks that generated any WAL.
 			 *
 			 * Sadly, we have no way of validating that this is really what
-			 * happened, and neither does the server. From it's perspective,
+			 * happened, and neither does the server.  From its perspective,
 			 * an unmodified block that contains data looks exactly the same
 			 * as a zero-filled block that never had any data: either way,
 			 * it's not mentioned in any WAL summary and the server has no

src/fe_utils/parallel_slot.c

@@ -347,11 +347,11 @@ connect_slot(ParallelSlotArray *sa, int slotno, const char *dbname)
  * returned allowing the connection to be reused.
  *
  * Otherwise, if any idle slot is not yet connected to any database, the slot
- * will be returned with it's connection opened using the stored cparams and
+ * will be returned with its connection opened using the stored cparams and
  * optionally the given dbname if not null.
  *
  * Otherwise, if any idle slot exists, an idle slot will be chosen and returned
- * after having it's connection disconnected and reconnected using the stored
+ * after having its connection disconnected and reconnected using the stored
  * cparams and optionally the given dbname if not null.
  *
  * Otherwise, if any slots have connections that are busy, we loop on select()

src/include/jit/SectionMemoryManager.h

@@ -182,7 +182,7 @@ private:
     // The actual block of free memory
     sys::MemoryBlock Free;
     // If there is a pending allocation from the same reservation right before
-    // this block, store it's index in PendingMem, to be able to update the
+    // this block, store its index in PendingMem, to be able to update the
     // pending region if part of this block is allocated, rather than having to
     // create a new one
     unsigned PendingPrefixIndex;

src/include/nodes/plannodes.h

@@ -1148,7 +1148,7 @@ typedef struct Gather
 	bool		single_copy;	/* don't execute plan more than once */
 	bool		invisible;		/* suppress EXPLAIN display (for testing)? */
 	Bitmapset  *initParam;		/* param id's of initplans which are referred
-								 * at gather or one of it's child node */
+								 * at gather or one of its child nodes */
 } Gather;
 
 /* ------------
@@ -1184,7 +1184,7 @@ typedef struct GatherMerge
 
 	/*
 	 * param id's of initplans which are referred at gather merge or one of
-	 * it's child node
+	 * its child nodes
 	 */
 	Bitmapset  *initParam;
 } GatherMerge;

src/pl/plpgsql/src/pl_exec.c

@@ -4690,7 +4690,7 @@ exec_stmt_open(PLpgSQL_execstate *estate, PLpgSQL_stmt_open *stmt)
 	}
 
 	/* ----------
-	 * Process the OPEN according to it's type.
+	 * Process the OPEN according to its type.
 	 * ----------
 	 */
 	if (stmt->query != NULL)

src/test/modules/test_slru/t/001_multixact.pl

@@ -58,7 +58,7 @@ $node->safe_psql('postgres',
 );
 
 # We expect this query to hang in the critical section after generating new
-# multixact, but before filling it's offset into SLRU.
+# multixact, but before filling its offset into SLRU.
 # Running an injection point inside a critical section requires it to be
 # loaded beforehand.
 $creator->query_until(

src/test/recovery/t/035_standby_logical_decoding.pl

@@ -822,7 +822,7 @@ check_pg_recvlogical_stderr($handle,
 );
 
 ##################################################
-# DROP DATABASE should drops it's slots, including active slots.
+# DROP DATABASE should drop its slots, including active slots.
 ##################################################
 
 # drop the logical slots