Adding upstream version 14.5.upstream/14.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1295 insertions, 0 deletions

diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c
new file mode 100644
index 0000000..15bef9f
--- /dev/null
+++ b/src/backend/access/heap/rewriteheap.c
@@ -0,0 +1,1295 @@
+/*-------------------------------------------------------------------------
+ *
+ * rewriteheap.c
+ *	  Support functions to rewrite tables.
+ *
+ * These functions provide a facility to completely rewrite a heap, while
+ * preserving visibility information and update chains.
+ *
+ * INTERFACE
+ *
+ * The caller is responsible for creating the new heap, all catalog
+ * changes, supplying the tuples to be written to the new heap, and
+ * rebuilding indexes.  The caller must hold AccessExclusiveLock on the
+ * target table, because we assume no one else is writing into it.
+ *
+ * To use the facility:
+ *
+ * begin_heap_rewrite
+ * while (fetch next tuple)
+ * {
+ *	   if (tuple is dead)
+ *		   rewrite_heap_dead_tuple
+ *	   else
+ *	   {
+ *		   // do any transformations here if required
+ *		   rewrite_heap_tuple
+ *	   }
+ * }
+ * end_heap_rewrite
+ *
+ * The contents of the new relation shouldn't be relied on until after
+ * end_heap_rewrite is called.
+ *
+ *
+ * IMPLEMENTATION
+ *
+ * This would be a fairly trivial affair, except that we need to maintain
+ * the ctid chains that link versions of an updated tuple together.
+ * Since the newly stored tuples will have tids different from the original
+ * ones, if we just copied t_ctid fields to the new table the links would
+ * be wrong.  When we are required to copy a (presumably recently-dead or
+ * delete-in-progress) tuple whose ctid doesn't point to itself, we have
+ * to substitute the correct ctid instead.
+ *
+ * For each ctid reference from A -> B, we might encounter either A first
+ * or B first.  (Note that a tuple in the middle of a chain is both A and B
+ * of different pairs.)
+ *
+ * If we encounter A first, we'll store the tuple in the unresolved_tups
+ * hash table. When we later encounter B, we remove A from the hash table,
+ * fix the ctid to point to the new location of B, and insert both A and B
+ * to the new heap.
+ *
+ * If we encounter B first, we can insert B to the new heap right away.
+ * We then add an entry to the old_new_tid_map hash table showing B's
+ * original tid (in the old heap) and new tid (in the new heap).
+ * When we later encounter A, we get the new location of B from the table,
+ * and can write A immediately with the correct ctid.
+ *
+ * Entries in the hash tables can be removed as soon as the later tuple
+ * is encountered.  That helps to keep the memory usage down.  At the end,
+ * both tables are usually empty; we should have encountered both A and B
+ * of each pair.  However, it's possible for A to be RECENTLY_DEAD and B
+ * entirely DEAD according to HeapTupleSatisfiesVacuum, because the test
+ * for deadness using OldestXmin is not exact.  In such a case we might
+ * encounter B first, and skip it, and find A later.  Then A would be added
+ * to unresolved_tups, and stay there until end of the rewrite.  Since
+ * this case is very unusual, we don't worry about the memory usage.
+ *
+ * Using in-memory hash tables means that we use some memory for each live
+ * update chain in the table, from the time we find one end of the
+ * reference until we find the other end.  That shouldn't be a problem in
+ * practice, but if you do something like an UPDATE without a where-clause
+ * on a large table, and then run CLUSTER in the same transaction, you
+ * could run out of memory.  It doesn't seem worthwhile to add support for
+ * spill-to-disk, as there shouldn't be that many RECENTLY_DEAD tuples in a
+ * table under normal circumstances.  Furthermore, in the typical scenario
+ * of CLUSTERing on an unchanging key column, we'll see all the versions
+ * of a given tuple together anyway, and so the peak memory usage is only
+ * proportional to the number of RECENTLY_DEAD versions of a single row, not
+ * in the whole table.  Note that if we do fail halfway through a CLUSTER,
+ * the old table is still valid, so failure is not catastrophic.
+ *
+ * We can't use the normal heap_insert function to insert into the new
+ * heap, because heap_insert overwrites the visibility information.
+ * We use a special-purpose raw_heap_insert function instead, which
+ * is optimized for bulk inserting a lot of tuples, knowing that we have
+ * exclusive access to the heap.  raw_heap_insert builds new pages in
+ * local storage.  When a page is full, or at the end of the process,
+ * we insert it to WAL as a single record and then write it to disk
+ * directly through smgr.  Note, however, that any data sent to the new
+ * heap's TOAST table will go through the normal bufmgr.
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994-5, Regents of the University of California
+ *
+ * IDENTIFICATION
+ *	  src/backend/access/heap/rewriteheap.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "access/heapam.h"
+#include "access/heapam_xlog.h"
+#include "access/heaptoast.h"
+#include "access/rewriteheap.h"
+#include "access/transam.h"
+#include "access/xact.h"
+#include "access/xloginsert.h"
+#include "catalog/catalog.h"
+#include "lib/ilist.h"
+#include "miscadmin.h"
+#include "pgstat.h"
+#include "replication/logical.h"
+#include "replication/slot.h"
+#include "storage/bufmgr.h"
+#include "storage/fd.h"
+#include "storage/procarray.h"
+#include "storage/smgr.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+
+/*
+ * State associated with a rewrite operation. This is opaque to the user
+ * of the rewrite facility.
+ */
+typedef struct RewriteStateData
+{
+	Relation	rs_old_rel;		/* source heap */
+	Relation	rs_new_rel;		/* destination heap */
+	Page		rs_buffer;		/* page currently being built */
+	BlockNumber rs_blockno;		/* block where page will go */
+	bool		rs_buffer_valid;	/* T if any tuples in buffer */
+	bool		rs_logical_rewrite; /* do we need to do logical rewriting */
+	TransactionId rs_oldest_xmin;	/* oldest xmin used by caller to determine
+									 * tuple visibility */
+	TransactionId rs_freeze_xid;	/* Xid that will be used as freeze cutoff
+									 * point */
+	TransactionId rs_logical_xmin;	/* Xid that will be used as cutoff point
+									 * for logical rewrites */
+	MultiXactId rs_cutoff_multi;	/* MultiXactId that will be used as cutoff
+									 * point for multixacts */
+	MemoryContext rs_cxt;		/* for hash tables and entries and tuples in
+								 * them */
+	XLogRecPtr	rs_begin_lsn;	/* XLogInsertLsn when starting the rewrite */
+	HTAB	   *rs_unresolved_tups; /* unmatched A tuples */
+	HTAB	   *rs_old_new_tid_map; /* unmatched B tuples */
+	HTAB	   *rs_logical_mappings;	/* logical remapping files */
+	uint32		rs_num_rewrite_mappings;	/* # in memory mappings */
+}			RewriteStateData;
+
+/*
+ * The lookup keys for the hash tables are tuple TID and xmin (we must check
+ * both to avoid false matches from dead tuples).  Beware that there is
+ * probably some padding space in this struct; it must be zeroed out for
+ * correct hashtable operation.
+ */
+typedef struct
+{
+	TransactionId xmin;			/* tuple xmin */
+	ItemPointerData tid;		/* tuple location in old heap */
+} TidHashKey;
+
+/*
+ * Entry structures for the hash tables
+ */
+typedef struct
+{
+	TidHashKey	key;			/* expected xmin/old location of B tuple */
+	ItemPointerData old_tid;	/* A's location in the old heap */
+	HeapTuple	tuple;			/* A's tuple contents */
+} UnresolvedTupData;
+
+typedef UnresolvedTupData *UnresolvedTup;
+
+typedef struct
+{
+	TidHashKey	key;			/* actual xmin/old location of B tuple */
+	ItemPointerData new_tid;	/* where we put it in the new heap */
+} OldToNewMappingData;
+
+typedef OldToNewMappingData *OldToNewMapping;
+
+/*
+ * In-Memory data for an xid that might need logical remapping entries
+ * to be logged.
+ */
+typedef struct RewriteMappingFile
+{
+	TransactionId xid;			/* xid that might need to see the row */
+	int			vfd;			/* fd of mappings file */
+	off_t		off;			/* how far have we written yet */
+	uint32		num_mappings;	/* number of in-memory mappings */
+	dlist_head	mappings;		/* list of in-memory mappings */
+	char		path[MAXPGPATH];	/* path, for error messages */
+} RewriteMappingFile;
+
+/*
+ * A single In-Memory logical rewrite mapping, hanging off
+ * RewriteMappingFile->mappings.
+ */
+typedef struct RewriteMappingDataEntry
+{
+	LogicalRewriteMappingData map;	/* map between old and new location of the
+									 * tuple */
+	dlist_node	node;
+} RewriteMappingDataEntry;
+
+
+/* prototypes for internal functions */
+static void raw_heap_insert(RewriteState state, HeapTuple tup);
+
+/* internal logical remapping prototypes */
+static void logical_begin_heap_rewrite(RewriteState state);
+static void logical_rewrite_heap_tuple(RewriteState state, ItemPointerData old_tid, HeapTuple new_tuple);
+static void logical_end_heap_rewrite(RewriteState state);
+
+
+/*
+ * Begin a rewrite of a table
+ *
+ * old_heap		old, locked heap relation tuples will be read from
+ * new_heap		new, locked heap relation to insert tuples to
+ * oldest_xmin	xid used by the caller to determine which tuples are dead
+ * freeze_xid	xid before which tuples will be frozen
+ * cutoff_multi	multixact before which multis will be removed
+ *
+ * Returns an opaque RewriteState, allocated in current memory context,
+ * to be used in subsequent calls to the other functions.
+ */
+RewriteState
+begin_heap_rewrite(Relation old_heap, Relation new_heap, TransactionId oldest_xmin,
+				   TransactionId freeze_xid, MultiXactId cutoff_multi)
+{
+	RewriteState state;
+	MemoryContext rw_cxt;
+	MemoryContext old_cxt;
+	HASHCTL		hash_ctl;
+
+	/*
+	 * To ease cleanup, make a separate context that will contain the
+	 * RewriteState struct itself plus all subsidiary data.
+	 */
+	rw_cxt = AllocSetContextCreate(CurrentMemoryContext,
+								   "Table rewrite",
+								   ALLOCSET_DEFAULT_SIZES);
+	old_cxt = MemoryContextSwitchTo(rw_cxt);
+
+	/* Create and fill in the state struct */
+	state = palloc0(sizeof(RewriteStateData));
+
+	state->rs_old_rel = old_heap;
+	state->rs_new_rel = new_heap;
+	state->rs_buffer = (Page) palloc(BLCKSZ);
+	/* new_heap needn't be empty, just locked */
+	state->rs_blockno = RelationGetNumberOfBlocks(new_heap);
+	state->rs_buffer_valid = false;
+	state->rs_oldest_xmin = oldest_xmin;
+	state->rs_freeze_xid = freeze_xid;
+	state->rs_cutoff_multi = cutoff_multi;
+	state->rs_cxt = rw_cxt;
+
+	/* Initialize hash tables used to track update chains */
+	hash_ctl.keysize = sizeof(TidHashKey);
+	hash_ctl.entrysize = sizeof(UnresolvedTupData);
+	hash_ctl.hcxt = state->rs_cxt;
+
+	state->rs_unresolved_tups =
+		hash_create("Rewrite / Unresolved ctids",
+					128,		/* arbitrary initial size */
+					&hash_ctl,
+					HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+
+	hash_ctl.entrysize = sizeof(OldToNewMappingData);
+
+	state->rs_old_new_tid_map =
+		hash_create("Rewrite / Old to new tid map",
+					128,		/* arbitrary initial size */
+					&hash_ctl,
+					HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+
+	MemoryContextSwitchTo(old_cxt);
+
+	logical_begin_heap_rewrite(state);
+
+	return state;
+}
+
+/*
+ * End a rewrite.
+ *
+ * state and any other resources are freed.
+ */
+void
+end_heap_rewrite(RewriteState state)
+{
+	HASH_SEQ_STATUS seq_status;
+	UnresolvedTup unresolved;
+
+	/*
+	 * Write any remaining tuples in the UnresolvedTups table. If we have any
+	 * left, they should in fact be dead, but let's err on the safe side.
+	 */
+	hash_seq_init(&seq_status, state->rs_unresolved_tups);
+
+	while ((unresolved = hash_seq_search(&seq_status)) != NULL)
+	{
+		ItemPointerSetInvalid(&unresolved->tuple->t_data->t_ctid);
+		raw_heap_insert(state, unresolved->tuple);
+	}
+
+	/* Write the last page, if any */
+	if (state->rs_buffer_valid)
+	{
+		if (RelationNeedsWAL(state->rs_new_rel))
+			log_newpage(&state->rs_new_rel->rd_node,
+						MAIN_FORKNUM,
+						state->rs_blockno,
+						state->rs_buffer,
+						true);
+
+		PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
+
+		RelationOpenSmgr(state->rs_new_rel);
+		smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM, state->rs_blockno,
+				   (char *) state->rs_buffer, true);
+	}
+
+	/*
+	 * When we WAL-logged rel pages, we must nonetheless fsync them.  The
+	 * reason is the same as in storage.c's RelationCopyStorage(): we're
+	 * writing data that's not in shared buffers, and so a CHECKPOINT
+	 * occurring during the rewriteheap operation won't have fsync'd data we
+	 * wrote before the checkpoint.
+	 */
+	if (RelationNeedsWAL(state->rs_new_rel))
+	{
+		/* for an empty table, this could be first smgr access */
+		RelationOpenSmgr(state->rs_new_rel);
+		smgrimmedsync(state->rs_new_rel->rd_smgr, MAIN_FORKNUM);
+	}
+
+	logical_end_heap_rewrite(state);
+
+	/* Deleting the context frees everything */
+	MemoryContextDelete(state->rs_cxt);
+}
+
+/*
+ * Add a tuple to the new heap.
+ *
+ * Visibility information is copied from the original tuple, except that
+ * we "freeze" very-old tuples.  Note that since we scribble on new_tuple,
+ * it had better be temp storage not a pointer to the original tuple.
+ *
+ * state		opaque state as returned by begin_heap_rewrite
+ * old_tuple	original tuple in the old heap
+ * new_tuple	new, rewritten tuple to be inserted to new heap
+ */
+void
+rewrite_heap_tuple(RewriteState state,
+				   HeapTuple old_tuple, HeapTuple new_tuple)
+{
+	MemoryContext old_cxt;
+	ItemPointerData old_tid;
+	TidHashKey	hashkey;
+	bool		found;
+	bool		free_new;
+
+	old_cxt = MemoryContextSwitchTo(state->rs_cxt);
+
+	/*
+	 * Copy the original tuple's visibility information into new_tuple.
+	 *
+	 * XXX we might later need to copy some t_infomask2 bits, too? Right now,
+	 * we intentionally clear the HOT status bits.
+	 */
+	memcpy(&new_tuple->t_data->t_choice.t_heap,
+		   &old_tuple->t_data->t_choice.t_heap,
+		   sizeof(HeapTupleFields));
+
+	new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
+	new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
+	new_tuple->t_data->t_infomask |=
+		old_tuple->t_data->t_infomask & HEAP_XACT_MASK;
+
+	/*
+	 * While we have our hands on the tuple, we may as well freeze any
+	 * eligible xmin or xmax, so that future VACUUM effort can be saved.
+	 */
+	heap_freeze_tuple(new_tuple->t_data,
+					  state->rs_old_rel->rd_rel->relfrozenxid,
+					  state->rs_old_rel->rd_rel->relminmxid,
+					  state->rs_freeze_xid,
+					  state->rs_cutoff_multi);
+
+	/*
+	 * Invalid ctid means that ctid should point to the tuple itself. We'll
+	 * override it later if the tuple is part of an update chain.
+	 */
+	ItemPointerSetInvalid(&new_tuple->t_data->t_ctid);
+
+	/*
+	 * If the tuple has been updated, check the old-to-new mapping hash table.
+	 */
+	if (!((old_tuple->t_data->t_infomask & HEAP_XMAX_INVALID) ||
+		  HeapTupleHeaderIsOnlyLocked(old_tuple->t_data)) &&
+		!HeapTupleHeaderIndicatesMovedPartitions(old_tuple->t_data) &&
+		!(ItemPointerEquals(&(old_tuple->t_self),
+							&(old_tuple->t_data->t_ctid))))
+	{
+		OldToNewMapping mapping;
+
+		memset(&hashkey, 0, sizeof(hashkey));
+		hashkey.xmin = HeapTupleHeaderGetUpdateXid(old_tuple->t_data);
+		hashkey.tid = old_tuple->t_data->t_ctid;
+
+		mapping = (OldToNewMapping)
+			hash_search(state->rs_old_new_tid_map, &hashkey,
+						HASH_FIND, NULL);
+
+		if (mapping != NULL)
+		{
+			/*
+			 * We've already copied the tuple that t_ctid points to, so we can
+			 * set the ctid of this tuple to point to the new location, and
+			 * insert it right away.
+			 */
+			new_tuple->t_data->t_ctid = mapping->new_tid;
+
+			/* We don't need the mapping entry anymore */
+			hash_search(state->rs_old_new_tid_map, &hashkey,
+						HASH_REMOVE, &found);
+			Assert(found);
+		}
+		else
+		{
+			/*
+			 * We haven't seen the tuple t_ctid points to yet. Stash this
+			 * tuple into unresolved_tups to be written later.
+			 */
+			UnresolvedTup unresolved;
+
+			unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
+									 HASH_ENTER, &found);
+			Assert(!found);
+
+			unresolved->old_tid = old_tuple->t_self;
+			unresolved->tuple = heap_copytuple(new_tuple);
+
+			/*
+			 * We can't do anything more now, since we don't know where the
+			 * tuple will be written.
+			 */
+			MemoryContextSwitchTo(old_cxt);
+			return;
+		}
+	}
+
+	/*
+	 * Now we will write the tuple, and then check to see if it is the B tuple
+	 * in any new or known pair.  When we resolve a known pair, we will be
+	 * able to write that pair's A tuple, and then we have to check if it
+	 * resolves some other pair.  Hence, we need a loop here.
+	 */
+	old_tid = old_tuple->t_self;
+	free_new = false;
+
+	for (;;)
+	{
+		ItemPointerData new_tid;
+
+		/* Insert the tuple and find out where it's put in new_heap */
+		raw_heap_insert(state, new_tuple);
+		new_tid = new_tuple->t_self;
+
+		logical_rewrite_heap_tuple(state, old_tid, new_tuple);
+
+		/*
+		 * If the tuple is the updated version of a row, and the prior version
+		 * wouldn't be DEAD yet, then we need to either resolve the prior
+		 * version (if it's waiting in rs_unresolved_tups), or make an entry
+		 * in rs_old_new_tid_map (so we can resolve it when we do see it). The
+		 * previous tuple's xmax would equal this one's xmin, so it's
+		 * RECENTLY_DEAD if and only if the xmin is not before OldestXmin.
+		 */
+		if ((new_tuple->t_data->t_infomask & HEAP_UPDATED) &&
+			!TransactionIdPrecedes(HeapTupleHeaderGetXmin(new_tuple->t_data),
+								   state->rs_oldest_xmin))
+		{
+			/*
+			 * Okay, this is B in an update pair.  See if we've seen A.
+			 */
+			UnresolvedTup unresolved;
+
+			memset(&hashkey, 0, sizeof(hashkey));
+			hashkey.xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
+			hashkey.tid = old_tid;
+
+			unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
+									 HASH_FIND, NULL);
+
+			if (unresolved != NULL)
+			{
+				/*
+				 * We have seen and memorized the previous tuple already. Now
+				 * that we know where we inserted the tuple its t_ctid points
+				 * to, fix its t_ctid and insert it to the new heap.
+				 */
+				if (free_new)
+					heap_freetuple(new_tuple);
+				new_tuple = unresolved->tuple;
+				free_new = true;
+				old_tid = unresolved->old_tid;
+				new_tuple->t_data->t_ctid = new_tid;
+
+				/*
+				 * We don't need the hash entry anymore, but don't free its
+				 * tuple just yet.
+				 */
+				hash_search(state->rs_unresolved_tups, &hashkey,
+							HASH_REMOVE, &found);
+				Assert(found);
+
+				/* loop back to insert the previous tuple in the chain */
+				continue;
+			}
+			else
+			{
+				/*
+				 * Remember the new tid of this tuple. We'll use it to set the
+				 * ctid when we find the previous tuple in the chain.
+				 */
+				OldToNewMapping mapping;
+
+				mapping = hash_search(state->rs_old_new_tid_map, &hashkey,
+									  HASH_ENTER, &found);
+				Assert(!found);
+
+				mapping->new_tid = new_tid;
+			}
+		}
+
+		/* Done with this (chain of) tuples, for now */
+		if (free_new)
+			heap_freetuple(new_tuple);
+		break;
+	}
+
+	MemoryContextSwitchTo(old_cxt);
+}
+
+/*
+ * Register a dead tuple with an ongoing rewrite. Dead tuples are not
+ * copied to the new table, but we still make note of them so that we
+ * can release some resources earlier.
+ *
+ * Returns true if a tuple was removed from the unresolved_tups table.
+ * This indicates that that tuple, previously thought to be "recently dead",
+ * is now known really dead and won't be written to the output.
+ */
+bool
+rewrite_heap_dead_tuple(RewriteState state, HeapTuple old_tuple)
+{
+	/*
+	 * If we have already seen an earlier tuple in the update chain that
+	 * points to this tuple, let's forget about that earlier tuple. It's in
+	 * fact dead as well, our simple xmax < OldestXmin test in
+	 * HeapTupleSatisfiesVacuum just wasn't enough to detect it. It happens
+	 * when xmin of a tuple is greater than xmax, which sounds
+	 * counter-intuitive but is perfectly valid.
+	 *
+	 * We don't bother to try to detect the situation the other way round,
+	 * when we encounter the dead tuple first and then the recently dead one
+	 * that points to it. If that happens, we'll have some unmatched entries
+	 * in the UnresolvedTups hash table at the end. That can happen anyway,
+	 * because a vacuum might have removed the dead tuple in the chain before
+	 * us.
+	 */
+	UnresolvedTup unresolved;
+	TidHashKey	hashkey;
+	bool		found;
+
+	memset(&hashkey, 0, sizeof(hashkey));
+	hashkey.xmin = HeapTupleHeaderGetXmin(old_tuple->t_data);
+	hashkey.tid = old_tuple->t_self;
+
+	unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
+							 HASH_FIND, NULL);
+
+	if (unresolved != NULL)
+	{
+		/* Need to free the contained tuple as well as the hashtable entry */
+		heap_freetuple(unresolved->tuple);
+		hash_search(state->rs_unresolved_tups, &hashkey,
+					HASH_REMOVE, &found);
+		Assert(found);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Insert a tuple to the new relation.  This has to track heap_insert
+ * and its subsidiary functions!
+ *
+ * t_self of the tuple is set to the new TID of the tuple. If t_ctid of the
+ * tuple is invalid on entry, it's replaced with the new TID as well (in
+ * the inserted data only, not in the caller's copy).
+ */
+static void
+raw_heap_insert(RewriteState state, HeapTuple tup)
+{
+	Page		page = state->rs_buffer;
+	Size		pageFreeSpace,
+				saveFreeSpace;
+	Size		len;
+	OffsetNumber newoff;
+	HeapTuple	heaptup;
+
+	/*
+	 * If the new tuple is too big for storage or contains already toasted
+	 * out-of-line attributes from some other relation, invoke the toaster.
+	 *
+	 * Note: below this point, heaptup is the data we actually intend to store
+	 * into the relation; tup is the caller's original untoasted data.
+	 */
+	if (state->rs_new_rel->rd_rel->relkind == RELKIND_TOASTVALUE)
+	{
+		/* toast table entries should never be recursively toasted */
+		Assert(!HeapTupleHasExternal(tup));
+		heaptup = tup;
+	}
+	else if (HeapTupleHasExternal(tup) || tup->t_len > TOAST_TUPLE_THRESHOLD)
+	{
+		int			options = HEAP_INSERT_SKIP_FSM;
+
+		/*
+		 * While rewriting the heap for VACUUM FULL / CLUSTER, make sure data
+		 * for the TOAST table are not logically decoded.  The main heap is
+		 * WAL-logged as XLOG FPI records, which are not logically decoded.
+		 */
+		options |= HEAP_INSERT_NO_LOGICAL;
+
+		heaptup = heap_toast_insert_or_update(state->rs_new_rel, tup, NULL,
+											  options);
+	}
+	else
+		heaptup = tup;
+
+	len = MAXALIGN(heaptup->t_len); /* be conservative */
+
+	/*
+	 * If we're gonna fail for oversize tuple, do it right away
+	 */
+	if (len > MaxHeapTupleSize)
+		ereport(ERROR,
+				(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
+				 errmsg("row is too big: size %zu, maximum size %zu",
+						len, MaxHeapTupleSize)));
+
+	/* Compute desired extra freespace due to fillfactor option */
+	saveFreeSpace = RelationGetTargetPageFreeSpace(state->rs_new_rel,
+												   HEAP_DEFAULT_FILLFACTOR);
+
+	/* Now we can check to see if there's enough free space already. */
+	if (state->rs_buffer_valid)
+	{
+		pageFreeSpace = PageGetHeapFreeSpace(page);
+
+		if (len + saveFreeSpace > pageFreeSpace)
+		{
+			/*
+			 * Doesn't fit, so write out the existing page.  It always
+			 * contains a tuple.  Hence, unlike RelationGetBufferForTuple(),
+			 * enforce saveFreeSpace unconditionally.
+			 */
+
+			/* XLOG stuff */
+			if (RelationNeedsWAL(state->rs_new_rel))
+				log_newpage(&state->rs_new_rel->rd_node,
+							MAIN_FORKNUM,
+							state->rs_blockno,
+							page,
+							true);
+
+			/*
+			 * Now write the page. We say skipFsync = true because there's no
+			 * need for smgr to schedule an fsync for this write; we'll do it
+			 * ourselves in end_heap_rewrite.
+			 */
+			RelationOpenSmgr(state->rs_new_rel);
+
+			PageSetChecksumInplace(page, state->rs_blockno);
+
+			smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM,
+					   state->rs_blockno, (char *) page, true);
+
+			state->rs_blockno++;
+			state->rs_buffer_valid = false;
+		}
+	}
+
+	if (!state->rs_buffer_valid)
+	{
+		/* Initialize a new empty page */
+		PageInit(page, BLCKSZ, 0);
+		state->rs_buffer_valid = true;
+	}
+
+	/* And now we can insert the tuple into the page */
+	newoff = PageAddItem(page, (Item) heaptup->t_data, heaptup->t_len,
+						 InvalidOffsetNumber, false, true);
+	if (newoff == InvalidOffsetNumber)
+		elog(ERROR, "failed to add tuple");
+
+	/* Update caller's t_self to the actual position where it was stored */
+	ItemPointerSet(&(tup->t_self), state->rs_blockno, newoff);
+
+	/*
+	 * Insert the correct position into CTID of the stored tuple, too, if the
+	 * caller didn't supply a valid CTID.
+	 */
+	if (!ItemPointerIsValid(&tup->t_data->t_ctid))
+	{
+		ItemId		newitemid;
+		HeapTupleHeader onpage_tup;
+
+		newitemid = PageGetItemId(page, newoff);
+		onpage_tup = (HeapTupleHeader) PageGetItem(page, newitemid);
+
+		onpage_tup->t_ctid = tup->t_self;
+	}
+
+	/* If heaptup is a private copy, release it. */
+	if (heaptup != tup)
+		heap_freetuple(heaptup);
+}
+
+/* ------------------------------------------------------------------------
+ * Logical rewrite support
+ *
+ * When doing logical decoding - which relies on using cmin/cmax of catalog
+ * tuples, via xl_heap_new_cid records - heap rewrites have to log enough
+ * information to allow the decoding backend to updates its internal mapping
+ * of (relfilenode,ctid) => (cmin, cmax) to be correct for the rewritten heap.
+ *
+ * For that, every time we find a tuple that's been modified in a catalog
+ * relation within the xmin horizon of any decoding slot, we log a mapping
+ * from the old to the new location.
+ *
+ * To deal with rewrites that abort the filename of a mapping file contains
+ * the xid of the transaction performing the rewrite, which then can be
+ * checked before being read in.
+ *
+ * For efficiency we don't immediately spill every single map mapping for a
+ * row to disk but only do so in batches when we've collected several of them
+ * in memory or when end_heap_rewrite() has been called.
+ *
+ * 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 exclusive locks on buffers. Usually the XLogInsert() covering
+ * buffer modifications is performed while the buffer(s) that are being
+ * 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.
+ *
+ * Instead we simply write the mapping files out to disk, *before* the
+ * XLogInsert() is performed. That guarantees that either the XLogInsert() is
+ * inserted after the checkpoint's redo pointer or that the checkpoint (via
+ * CheckPointLogicalRewriteHeap()) has flushed the (partial) mapping file to
+ * disk. That leaves the tail end that has not yet been flushed open to
+ * corruption, which is solved by including the current offset in the
+ * xl_heap_rewrite_mapping records and truncating the mapping file to it
+ * during replay. Every time a rewrite is finished all generated mapping files
+ * are synced to disk.
+ *
+ * Note that if we were only concerned about crash safety we wouldn't have to
+ * deal with WAL logging at all - an fsync() at the end of a rewrite would be
+ * sufficient for crash safety. Any mapping that hasn't been safely flushed to
+ * disk has to be by an aborted (explicitly or via a crash) transaction and is
+ * ignored by virtue of the xid in its name being subject to a
+ * TransactionDidCommit() check. But we want to support having standbys via
+ * physical replication, both for availability and to do logical decoding
+ * there.
+ * ------------------------------------------------------------------------
+ */
+
+/*
+ * Do preparations for logging logical mappings during a rewrite if
+ * necessary. If we detect that we don't need to log anything we'll prevent
+ * any further action by the various logical rewrite functions.
+ */
+static void
+logical_begin_heap_rewrite(RewriteState state)
+{
+	HASHCTL		hash_ctl;
+	TransactionId logical_xmin;
+
+	/*
+	 * We only need to persist these mappings if the rewritten table can be
+	 * accessed during logical decoding, if not, we can skip doing any
+	 * additional work.
+	 */
+	state->rs_logical_rewrite =
+		RelationIsAccessibleInLogicalDecoding(state->rs_old_rel);
+
+	if (!state->rs_logical_rewrite)
+		return;
+
+	ProcArrayGetReplicationSlotXmin(NULL, &logical_xmin);
+
+	/*
+	 * If there are no logical slots in progress we don't need to do anything,
+	 * there cannot be any remappings for relevant rows yet. The relation's
+	 * lock protects us against races.
+	 */
+	if (logical_xmin == InvalidTransactionId)
+	{
+		state->rs_logical_rewrite = false;
+		return;
+	}
+
+	state->rs_logical_xmin = logical_xmin;
+	state->rs_begin_lsn = GetXLogInsertRecPtr();
+	state->rs_num_rewrite_mappings = 0;
+
+	hash_ctl.keysize = sizeof(TransactionId);
+	hash_ctl.entrysize = sizeof(RewriteMappingFile);
+	hash_ctl.hcxt = state->rs_cxt;
+
+	state->rs_logical_mappings =
+		hash_create("Logical rewrite mapping",
+					128,		/* arbitrary initial size */
+					&hash_ctl,
+					HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
+}
+
+/*
+ * Flush all logical in-memory mappings to disk, but don't fsync them yet.
+ */
+static void
+logical_heap_rewrite_flush_mappings(RewriteState state)
+{
+	HASH_SEQ_STATUS seq_status;
+	RewriteMappingFile *src;
+	dlist_mutable_iter iter;
+
+	Assert(state->rs_logical_rewrite);
+
+	/* no logical rewrite in progress, no need to iterate over mappings */
+	if (state->rs_num_rewrite_mappings == 0)
+		return;
+
+	elog(DEBUG1, "flushing %u logical rewrite mapping entries",
+		 state->rs_num_rewrite_mappings);
+
+	hash_seq_init(&seq_status, state->rs_logical_mappings);
+	while ((src = (RewriteMappingFile *) hash_seq_search(&seq_status)) != NULL)
+	{
+		char	   *waldata;
+		char	   *waldata_start;
+		xl_heap_rewrite_mapping xlrec;
+		Oid			dboid;
+		uint32		len;
+		int			written;
+
+		/* this file hasn't got any new mappings */
+		if (src->num_mappings == 0)
+			continue;
+
+		if (state->rs_old_rel->rd_rel->relisshared)
+			dboid = InvalidOid;
+		else
+			dboid = MyDatabaseId;
+
+		xlrec.num_mappings = src->num_mappings;
+		xlrec.mapped_rel = RelationGetRelid(state->rs_old_rel);
+		xlrec.mapped_xid = src->xid;
+		xlrec.mapped_db = dboid;
+		xlrec.offset = src->off;
+		xlrec.start_lsn = state->rs_begin_lsn;
+
+		/* write all mappings consecutively */
+		len = src->num_mappings * sizeof(LogicalRewriteMappingData);
+		waldata_start = waldata = palloc(len);
+
+		/*
+		 * collect data we need to write out, but don't modify ondisk data yet
+		 */
+		dlist_foreach_modify(iter, &src->mappings)
+		{
+			RewriteMappingDataEntry *pmap;
+
+			pmap = dlist_container(RewriteMappingDataEntry, node, iter.cur);
+
+			memcpy(waldata, &pmap->map, sizeof(pmap->map));
+			waldata += sizeof(pmap->map);
+
+			/* remove from the list and free */
+			dlist_delete(&pmap->node);
+			pfree(pmap);
+
+			/* update bookkeeping */
+			state->rs_num_rewrite_mappings--;
+			src->num_mappings--;
+		}
+
+		Assert(src->num_mappings == 0);
+		Assert(waldata == waldata_start + len);
+
+		/*
+		 * Note that we deviate from the usual WAL coding practices here,
+		 * check the above "Logical rewrite support" comment for reasoning.
+		 */
+		written = FileWrite(src->vfd, waldata_start, len, src->off,
+							WAIT_EVENT_LOGICAL_REWRITE_WRITE);
+		if (written != len)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not write to file \"%s\", wrote %d of %d: %m", src->path,
+							written, len)));
+		src->off += len;
+
+		XLogBeginInsert();
+		XLogRegisterData((char *) (&xlrec), sizeof(xlrec));
+		XLogRegisterData(waldata_start, len);
+
+		/* write xlog record */
+		XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_REWRITE);
+
+		pfree(waldata_start);
+	}
+	Assert(state->rs_num_rewrite_mappings == 0);
+}
+
+/*
+ * Logical remapping part of end_heap_rewrite().
+ */
+static void
+logical_end_heap_rewrite(RewriteState state)
+{
+	HASH_SEQ_STATUS seq_status;
+	RewriteMappingFile *src;
+
+	/* done, no logical rewrite in progress */
+	if (!state->rs_logical_rewrite)
+		return;
+
+	/* writeout remaining in-memory entries */
+	if (state->rs_num_rewrite_mappings > 0)
+		logical_heap_rewrite_flush_mappings(state);
+
+	/* Iterate over all mappings we have written and fsync the files. */
+	hash_seq_init(&seq_status, state->rs_logical_mappings);
+	while ((src = (RewriteMappingFile *) hash_seq_search(&seq_status)) != NULL)
+	{
+		if (FileSync(src->vfd, WAIT_EVENT_LOGICAL_REWRITE_SYNC) != 0)
+			ereport(data_sync_elevel(ERROR),
+					(errcode_for_file_access(),
+					 errmsg("could not fsync file \"%s\": %m", src->path)));
+		FileClose(src->vfd);
+	}
+	/* memory context cleanup will deal with the rest */
+}
+
+/*
+ * Log a single (old->new) mapping for 'xid'.
+ */
+static void
+logical_rewrite_log_mapping(RewriteState state, TransactionId xid,
+							LogicalRewriteMappingData *map)
+{
+	RewriteMappingFile *src;
+	RewriteMappingDataEntry *pmap;
+	Oid			relid;
+	bool		found;
+
+	relid = RelationGetRelid(state->rs_old_rel);
+
+	/* look for existing mappings for this 'mapped' xid */
+	src = hash_search(state->rs_logical_mappings, &xid,
+					  HASH_ENTER, &found);
+
+	/*
+	 * We haven't yet had the need to map anything for this xid, create
+	 * per-xid data structures.
+	 */
+	if (!found)
+	{
+		char		path[MAXPGPATH];
+		Oid			dboid;
+
+		if (state->rs_old_rel->rd_rel->relisshared)
+			dboid = InvalidOid;
+		else
+			dboid = MyDatabaseId;
+
+		snprintf(path, MAXPGPATH,
+				 "pg_logical/mappings/" LOGICAL_REWRITE_FORMAT,
+				 dboid, relid,
+				 LSN_FORMAT_ARGS(state->rs_begin_lsn),
+				 xid, GetCurrentTransactionId());
+
+		dlist_init(&src->mappings);
+		src->num_mappings = 0;
+		src->off = 0;
+		memcpy(src->path, path, sizeof(path));
+		src->vfd = PathNameOpenFile(path,
+									O_CREAT | O_EXCL | O_WRONLY | PG_BINARY);
+		if (src->vfd < 0)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not create file \"%s\": %m", path)));
+	}
+
+	pmap = MemoryContextAlloc(state->rs_cxt,
+							  sizeof(RewriteMappingDataEntry));
+	memcpy(&pmap->map, map, sizeof(LogicalRewriteMappingData));
+	dlist_push_tail(&src->mappings, &pmap->node);
+	src->num_mappings++;
+	state->rs_num_rewrite_mappings++;
+
+	/*
+	 * Write out buffer every time we've too many in-memory entries across all
+	 * mapping files.
+	 */
+	if (state->rs_num_rewrite_mappings >= 1000 /* arbitrary number */ )
+		logical_heap_rewrite_flush_mappings(state);
+}
+
+/*
+ * Perform logical remapping for a tuple that's mapped from old_tid to
+ * new_tuple->t_self by rewrite_heap_tuple() if necessary for the tuple.
+ */
+static void
+logical_rewrite_heap_tuple(RewriteState state, ItemPointerData old_tid,
+						   HeapTuple new_tuple)
+{
+	ItemPointerData new_tid = new_tuple->t_self;
+	TransactionId cutoff = state->rs_logical_xmin;
+	TransactionId xmin;
+	TransactionId xmax;
+	bool		do_log_xmin = false;
+	bool		do_log_xmax = false;
+	LogicalRewriteMappingData map;
+
+	/* no logical rewrite in progress, we don't need to log anything */
+	if (!state->rs_logical_rewrite)
+		return;
+
+	xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
+	/* use *GetUpdateXid to correctly deal with multixacts */
+	xmax = HeapTupleHeaderGetUpdateXid(new_tuple->t_data);
+
+	/*
+	 * Log the mapping iff the tuple has been created recently.
+	 */
+	if (TransactionIdIsNormal(xmin) && !TransactionIdPrecedes(xmin, cutoff))
+		do_log_xmin = true;
+
+	if (!TransactionIdIsNormal(xmax))
+	{
+		/*
+		 * no xmax is set, can't have any permanent ones, so this check is
+		 * sufficient
+		 */
+	}
+	else if (HEAP_XMAX_IS_LOCKED_ONLY(new_tuple->t_data->t_infomask))
+	{
+		/* only locked, we don't care */
+	}
+	else if (!TransactionIdPrecedes(xmax, cutoff))
+	{
+		/* tuple has been deleted recently, log */
+		do_log_xmax = true;
+	}
+
+	/* if neither needs to be logged, we're done */
+	if (!do_log_xmin && !do_log_xmax)
+		return;
+
+	/* fill out mapping information */
+	map.old_node = state->rs_old_rel->rd_node;
+	map.old_tid = old_tid;
+	map.new_node = state->rs_new_rel->rd_node;
+	map.new_tid = new_tid;
+
+	/* ---
+	 * Now persist the mapping for the individual xids that are affected. We
+	 * need to log for both xmin and xmax if they aren't the same transaction
+	 * since the mapping files are per "affected" xid.
+	 * We don't muster all that much effort detecting whether xmin and xmax
+	 * are actually the same transaction, we just check whether the xid is the
+	 * same disregarding subtransactions. Logging too much is relatively
+	 * harmless and we could never do the check fully since subtransaction
+	 * data is thrown away during restarts.
+	 * ---
+	 */
+	if (do_log_xmin)
+		logical_rewrite_log_mapping(state, xmin, &map);
+	/* separately log mapping for xmax unless it'd be redundant */
+	if (do_log_xmax && !TransactionIdEquals(xmin, xmax))
+		logical_rewrite_log_mapping(state, xmax, &map);
+}
+
+/*
+ * Replay XLOG_HEAP2_REWRITE records
+ */
+void
+heap_xlog_logical_rewrite(XLogReaderState *r)
+{
+	char		path[MAXPGPATH];
+	int			fd;
+	xl_heap_rewrite_mapping *xlrec;
+	uint32		len;
+	char	   *data;
+
+	xlrec = (xl_heap_rewrite_mapping *) XLogRecGetData(r);
+
+	snprintf(path, MAXPGPATH,
+			 "pg_logical/mappings/" LOGICAL_REWRITE_FORMAT,
+			 xlrec->mapped_db, xlrec->mapped_rel,
+			 LSN_FORMAT_ARGS(xlrec->start_lsn),
+			 xlrec->mapped_xid, XLogRecGetXid(r));
+
+	fd = OpenTransientFile(path,
+						   O_CREAT | O_WRONLY | PG_BINARY);
+	if (fd < 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not create file \"%s\": %m", path)));
+
+	/*
+	 * Truncate all data that's not guaranteed to have been safely fsynced (by
+	 * previous record or by the last checkpoint).
+	 */
+	pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_TRUNCATE);
+	if (ftruncate(fd, xlrec->offset) != 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not truncate file \"%s\" to %u: %m",
+						path, (uint32) xlrec->offset)));
+	pgstat_report_wait_end();
+
+	data = XLogRecGetData(r) + sizeof(*xlrec);
+
+	len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData);
+
+	/* write out tail end of mapping file (again) */
+	errno = 0;
+	pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE);
+	if (pg_pwrite(fd, data, len, xlrec->offset) != len)
+	{
+		/* if write didn't set errno, assume problem is no disk space */
+		if (errno == 0)
+			errno = ENOSPC;
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not write to file \"%s\": %m", path)));
+	}
+	pgstat_report_wait_end();
+
+	/*
+	 * Now fsync all previously written data. We could improve things and only
+	 * do this for the last write to a file, but the required bookkeeping
+	 * doesn't seem worth the trouble.
+	 */
+	pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_SYNC);
+	if (pg_fsync(fd) != 0)
+		ereport(data_sync_elevel(ERROR),
+				(errcode_for_file_access(),
+				 errmsg("could not fsync file \"%s\": %m", path)));
+	pgstat_report_wait_end();
+
+	if (CloseTransientFile(fd) != 0)
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				 errmsg("could not close file \"%s\": %m", path)));
+}
+
+/* ---
+ * Perform a checkpoint for logical rewrite mappings
+ *
+ * This serves two tasks:
+ * 1) Remove all mappings not needed anymore based on the logical restart LSN
+ * 2) Flush all remaining mappings to disk, so that replay after a checkpoint
+ *	  only has to deal with the parts of a mapping that have been written out
+ *	  after the checkpoint started.
+ * ---
+ */
+void
+CheckPointLogicalRewriteHeap(void)
+{
+	XLogRecPtr	cutoff;
+	XLogRecPtr	redo;
+	DIR		   *mappings_dir;
+	struct dirent *mapping_de;
+	char		path[MAXPGPATH + 20];
+
+	/*
+	 * We start of with a minimum of the last redo pointer. No new decoding
+	 * slot will start before that, so that's a safe upper bound for removal.
+	 */
+	redo = GetRedoRecPtr();
+
+	/* now check for the restart ptrs from existing slots */
+	cutoff = ReplicationSlotsComputeLogicalRestartLSN();
+
+	/* don't start earlier than the restart lsn */
+	if (cutoff != InvalidXLogRecPtr && redo < cutoff)
+		cutoff = redo;
+
+	mappings_dir = AllocateDir("pg_logical/mappings");
+	while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
+	{
+		struct stat statbuf;
+		Oid			dboid;
+		Oid			relid;
+		XLogRecPtr	lsn;
+		TransactionId rewrite_xid;
+		TransactionId create_xid;
+		uint32		hi,
+					lo;
+
+		if (strcmp(mapping_de->d_name, ".") == 0 ||
+			strcmp(mapping_de->d_name, "..") == 0)
+			continue;
+
+		snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
+		if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
+			continue;
+
+		/* Skip over files that cannot be ours. */
+		if (strncmp(mapping_de->d_name, "map-", 4) != 0)
+			continue;
+
+		if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
+				   &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
+			elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
+
+		lsn = ((uint64) hi) << 32 | lo;
+
+		if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
+		{
+			elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
+			if (unlink(path) < 0)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not remove file \"%s\": %m", path)));
+		}
+		else
+		{
+			/* on some operating systems fsyncing a file requires O_RDWR */
+			int			fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
+
+			/*
+			 * The file cannot vanish due to concurrency since this function
+			 * is the only one removing logical mappings and only one
+			 * checkpoint can be in progress at a time.
+			 */
+			if (fd < 0)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not open file \"%s\": %m", path)));
+
+			/*
+			 * We could try to avoid fsyncing files that either haven't
+			 * changed or have only been created since the checkpoint's start,
+			 * but it's currently not deemed worth the effort.
+			 */
+			pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC);
+			if (pg_fsync(fd) != 0)
+				ereport(data_sync_elevel(ERROR),
+						(errcode_for_file_access(),
+						 errmsg("could not fsync file \"%s\": %m", path)));
+			pgstat_report_wait_end();
+
+			if (CloseTransientFile(fd) != 0)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+						 errmsg("could not close file \"%s\": %m", path)));
+		}
+	}
+	FreeDir(mappings_dir);
+
+	/* persist directory entries to disk */
+	fsync_fname("pg_logical/mappings", true);
+}