Rename "pg_clog" directory to "pg_xact".

Names containing the letters "log" sometimes confuse users into
believing that only non-critical data is present.  It is hoped
this renaming will discourage ill-considered removals of transaction
status data.

Michael Paquier

Discussion: http://postgr.es/m/CA+Tgmoa9xFQyjRZupbdEFuwUerFTvC6HjZq1ud6GYragGDFFgA@mail.gmail.com

19 files changed, 65 insertions, 54 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index bffc971d689..85261379b1f 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6790,8 +6790,8 @@ heap_prepare_freeze_tuple(HeapTupleHeader tuple, TransactionId cutoff_xid,
  * Note: it might seem we could make the changes without exclusive lock, since
  * TransactionId read/write is assumed atomic anyway.  However there is a race
  * condition: someone who just fetched an old XID that we overwrite here could
- * conceivably not finish checking the XID against pg_clog before we finish
- * the VACUUM and perhaps truncate off the part of pg_clog he needs.  Getting
+ * conceivably not finish checking the XID against pg_xact before we finish
+ * the VACUUM and perhaps truncate off the part of pg_xact he needs.  Getting
  * exclusive lock ensures no other backend is in process of checking the
  * tuple status.  Also, getting exclusive lock makes it safe to adjust the
  * infomask bits.
diff --git a/src/backend/access/transam/README b/src/backend/access/transam/README
index 4ae4715339e..e7dd19fd7b9 100644
--- a/src/backend/access/transam/README
+++ b/src/backend/access/transam/README
@@ -331,17 +331,17 @@ of the xid fields is atomic, so assuming it for xmin as well is no extra
 risk.
 
 
-pg_clog and pg_subtrans
+pg_xact and pg_subtrans
 -----------------------
 
-pg_clog and pg_subtrans are permanent (on-disk) storage of transaction related
+pg_xact and pg_subtrans are permanent (on-disk) storage of transaction related
 information.  There is a limited number of pages of each kept in memory, so
 in many cases there is no need to actually read from disk.  However, if
 there's a long running transaction or a backend sitting idle with an open
 transaction, it may be necessary to be able to read and write this information
 from disk.  They also allow information to be permanent across server restarts.
 
-pg_clog records the commit status for each transaction that has been assigned
+pg_xact records the commit status for each transaction that has been assigned
 an XID.  A transaction can be in progress, committed, aborted, or
 "sub-committed".  This last state means that it's a subtransaction that's no
 longer running, but its parent has not updated its state yet.  It is not
@@ -381,9 +381,9 @@ each transaction we keep a "cache" of Xids that are known to be part of the
 transaction tree, so we can skip looking at pg_subtrans unless we know the
 cache has been overflowed.  See storage/ipc/procarray.c for the gory details.
 
-slru.c is the supporting mechanism for both pg_clog and pg_subtrans.  It
+slru.c is the supporting mechanism for both pg_xact and pg_subtrans.  It
 implements the LRU policy for in-memory buffer pages.  The high-level routines
-for pg_clog are implemented in transam.c, while the low-level functions are in
+for pg_xact are implemented in transam.c, while the low-level functions are in
 clog.c.  pg_subtrans is contained completely in subtrans.c.
 
 
diff --git a/src/backend/access/transam/clog.c b/src/backend/access/transam/clog.c
index 1a43819736a..5b1d13dac1b 100644
--- a/src/backend/access/transam/clog.c
+++ b/src/backend/access/transam/clog.c
@@ -450,7 +450,7 @@ CLOGShmemInit(void)
 {
 	ClogCtl->PagePrecedes = CLOGPagePrecedes;
 	SimpleLruInit(ClogCtl, "clog", CLOGShmemBuffers(), CLOG_LSNS_PER_PAGE,
-				  CLogControlLock, "pg_clog", LWTRANCHE_CLOG_BUFFERS);
+				  CLogControlLock, "pg_xact", LWTRANCHE_CLOG_BUFFERS);
 }
 
 /*
diff --git a/src/backend/access/transam/commit_ts.c b/src/backend/access/transam/commit_ts.c
index 20f60bc0236..8e1df6e0eab 100644
--- a/src/backend/access/transam/commit_ts.c
+++ b/src/backend/access/transam/commit_ts.c
@@ -3,7 +3,7 @@
  * commit_ts.c
  *		PostgreSQL commit timestamp manager
  *
- * This module is a pg_clog-like system that stores the commit timestamp
+ * This module is a pg_xact-like system that stores the commit timestamp
  * for each transaction.
  *
  * XLOG interactions: this module generates an XLOG record whenever a new
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index c350dfa17fe..1a7824b5d44 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -3,7 +3,7 @@
  * multixact.c
  *		PostgreSQL multi-transaction-log manager
  *
- * The pg_multixact manager is a pg_clog-like manager that stores an array of
+ * The pg_multixact manager is a pg_xact-like manager that stores an array of
  * MultiXactMember for each MultiXactId.  It is a fundamental part of the
  * shared-row-lock implementation.  Each MultiXactMember is comprised of a
  * TransactionId and a set of flag bits.  The name is a bit historical:
diff --git a/src/backend/access/transam/subtrans.c b/src/backend/access/transam/subtrans.c
index a66fc0f2ad5..70828e51703 100644
--- a/src/backend/access/transam/subtrans.c
+++ b/src/backend/access/transam/subtrans.c
@@ -3,15 +3,14 @@
  * subtrans.c
  *		PostgreSQL subtransaction-log manager
  *
- * The pg_subtrans manager is a pg_clog-like manager that stores the parent
+ * The pg_subtrans manager is a pg_xact-like manager that stores the parent
  * transaction Id for each transaction.  It is a fundamental part of the
  * nested transactions implementation.  A main transaction has a parent
  * of InvalidTransactionId, and each subtransaction has its immediate parent.
  * The tree can easily be walked from child to parent, but not in the
  * opposite direction.
  *
- * This code is based on clog.c, but the robustness requirements
- * are completely different from pg_clog, because we only need to remember
+ * are completely different from pg_xact, because we only need to remember
  * pg_subtrans information for currently-open transactions.  Thus, there is
  * no need to preserve data over a crash and restart.
  *
diff --git a/src/backend/access/transam/transam.c b/src/backend/access/transam/transam.c
index c2b4318bd30..b91a259e806 100644
--- a/src/backend/access/transam/transam.c
+++ b/src/backend/access/transam/transam.c
@@ -224,7 +224,7 @@ TransactionIdDidAbort(TransactionId transactionId)
  *		True iff transaction associated with the identifier is currently
  *		known to have either committed or aborted.
  *
- * This does NOT look into pg_clog but merely probes our local cache
+ * This does NOT look into pg_xact but merely probes our local cache
  * (and so it's not named TransactionIdDidComplete, which would be the
  * appropriate name for a function that worked that way).  The intended
  * use is just to short-circuit TransactionIdIsInProgress calls when doing
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index 83ca6e04081..da77e3efde4 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -1379,7 +1379,7 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
 	/*
 	 * The order of operations here is critical: make the XLOG entry for
 	 * commit or abort, then mark the transaction committed or aborted in
-	 * pg_clog, then remove its PGPROC from the global ProcArray (which means
+	 * pg_xact, then remove its PGPROC from the global ProcArray (which means
 	 * TransactionIdIsInProgress will stop saying the prepared xact is in
 	 * progress), then run the post-commit or post-abort callbacks. The
 	 * callbacks will release the locks the transaction held.
@@ -2093,7 +2093,7 @@ RecordTransactionCommitPrepared(TransactionId xid,
 	/* Flush XLOG to disk */
 	XLogFlush(recptr);
 
-	/* Mark the transaction committed in pg_clog */
+	/* Mark the transaction committed in pg_xact */
 	TransactionIdCommitTree(xid, nchildren, children);
 
 	/* Checkpoint can proceed now */
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 82f9a3c5c6c..02e0779f325 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -1208,8 +1208,8 @@ RecordTransactionCommit(void)
 		/*
 		 * Mark ourselves as within our "commit critical section".  This
 		 * forces any concurrent checkpoint to wait until we've updated
-		 * pg_clog.  Without this, it is possible for the checkpoint to set
-		 * REDO after the XLOG record but fail to flush the pg_clog update to
+		 * pg_xact.  Without this, it is possible for the checkpoint to set
+		 * REDO after the XLOG record but fail to flush the pg_xact update to
 		 * disk, leading to loss of the transaction commit if the system
 		 * crashes a little later.
 		 *
@@ -2035,7 +2035,7 @@ CommitTransaction(void)
 	if (!is_parallel_worker)
 	{
 		/*
-		 * We need to mark our XIDs as committed in pg_clog.  This is where we
+		 * We need to mark our XIDs as committed in pg_xact.  This is where we
 		 * durably commit.
 		 */
 		latestXid = RecordTransactionCommit();
@@ -2545,7 +2545,7 @@ AbortTransaction(void)
 	AtAbort_Twophase();
 
 	/*
-	 * Advertise the fact that we aborted in pg_clog (assuming that we got as
+	 * Advertise the fact that we aborted in pg_xact (assuming that we got as
 	 * far as assigning an XID to advertise).  But if we're inside a parallel
 	 * worker, skip this; the user backend must be the one to write the abort
 	 * record.
@@ -4631,7 +4631,7 @@ AbortSubTransaction(void)
 								s->parent->subTransactionId);
 		AtSubAbort_Notify();
 
-		/* Advertise the fact that we aborted in pg_clog. */
+		/* Advertise the fact that we aborted in pg_xact. */
 		(void) RecordTransactionAbort(true);
 
 		/* Post-abort cleanup */
@@ -5375,7 +5375,7 @@ xact_redo_commit(xl_xact_parsed_commit *parsed,
 	if (standbyState == STANDBY_DISABLED)
 	{
 		/*
-		 * Mark the transaction committed in pg_clog.
+		 * Mark the transaction committed in pg_xact.
 		 */
 		TransactionIdCommitTree(xid, parsed->nsubxacts, parsed->subxacts);
 	}
@@ -5393,7 +5393,7 @@ xact_redo_commit(xl_xact_parsed_commit *parsed,
 		RecordKnownAssignedTransactionIds(max_xid);
 
 		/*
-		 * Mark the transaction committed in pg_clog. We use async commit
+		 * Mark the transaction committed in pg_xact. We use async commit
 		 * protocol during recovery to provide information on database
 		 * consistency for when users try to set hint bits. It is important
 		 * that we do not set hint bits until the minRecoveryPoint is past
@@ -5530,7 +5530,7 @@ xact_redo_abort(xl_xact_parsed_abort *parsed, TransactionId xid)
 
 	if (standbyState == STANDBY_DISABLED)
 	{
-		/* Mark the transaction aborted in pg_clog, no need for async stuff */
+		/* Mark the transaction aborted in pg_xact, no need for async stuff */
 		TransactionIdAbortTree(xid, parsed->nsubxacts, parsed->subxacts);
 	}
 	else
@@ -5546,7 +5546,7 @@ xact_redo_abort(xl_xact_parsed_abort *parsed, TransactionId xid)
 		 */
 		RecordKnownAssignedTransactionIds(max_xid);
 
-		/* Mark the transaction aborted in pg_clog, no need for async stuff */
+		/* Mark the transaction aborted in pg_xact, no need for async stuff */
 		TransactionIdAbortTree(xid, parsed->nsubxacts, parsed->subxacts);
 
 		/*
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 64335f909e3..cdb3a8ac1dc 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8710,7 +8710,7 @@ CreateCheckPoint(int flags)
 	 * that are currently in commit critical sections.  If an xact inserted
 	 * its commit record into XLOG just before the REDO point, then a crash
 	 * restart from the REDO point would not replay that record, which means
-	 * that our flushing had better include the xact's update of pg_clog.  So
+	 * that our flushing had better include the xact's update of pg_xact.  So
 	 * we wait till he's out of his commit critical section before proceeding.
 	 * See notes in RecordTransactionCommit().
 	 *
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 3b3dfeead4f..ff633faca64 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -357,7 +357,7 @@ vacuum(int options, RangeVar *relation, Oid relid, VacuumParams *params,
 	if ((options & VACOPT_VACUUM) && !IsAutoVacuumWorkerProcess())
 	{
 		/*
-		 * Update pg_database.datfrozenxid, and truncate pg_clog if possible.
+		 * Update pg_database.datfrozenxid, and truncate pg_xact if possible.
 		 * (autovacuum.c does this for itself.)
 		 */
 		vac_update_datfrozenxid();
@@ -910,7 +910,7 @@ vac_update_relstats(Relation relation,
  *		pg_class.relminmxid values.
  *
  *		If we are able to advance either pg_database value, also try to
- *		truncate pg_clog and pg_multixact.
+ *		truncate pg_xact and pg_multixact.
  *
  *		We violate transaction semantics here by overwriting the database's
  *		existing pg_database tuple with the new values.  This is reasonably
@@ -1056,7 +1056,7 @@ vac_update_datfrozenxid(void)
 
 	/*
 	 * If we were able to advance datfrozenxid or datminmxid, see if we can
-	 * truncate pg_clog and/or pg_multixact.  Also do it if the shared
+	 * truncate pg_xact and/or pg_multixact.  Also do it if the shared
 	 * XID-wrap-limit info is stale, since this action will update that too.
 	 */
 	if (dirty || ForceTransactionIdLimitUpdate())
@@ -1069,7 +1069,7 @@ vac_update_datfrozenxid(void)
  *	vac_truncate_clog() -- attempt to truncate the commit log
  *
  *		Scan pg_database to determine the system-wide oldest datfrozenxid,
- *		and use it to truncate the transaction commit log (pg_clog).
+ *		and use it to truncate the transaction commit log (pg_xact).
  *		Also update the XID wrap limit info maintained by varsup.c.
  *		Likewise for datminmxid.
  *
@@ -1116,7 +1116,7 @@ vac_truncate_clog(TransactionId frozenXID,
 	 * of the interlock against copying a DB containing an active backend.
 	 * Hence the new entry will not reduce the minimum.  Also, if two VACUUMs
 	 * concurrently modify the datfrozenxid's of different databases, the
-	 * worst possible outcome is that pg_clog is not truncated as aggressively
+	 * worst possible outcome is that pg_xact is not truncated as aggressively
 	 * as it could be.
 	 */
 	relation = heap_open(DatabaseRelationId, AccessShareLock);
diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index fa8de1390e5..33ca749b529 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -2472,7 +2472,7 @@ deleted:
 	 */
 
 	/*
-	 * Update pg_database.datfrozenxid, and truncate pg_clog if possible. We
+	 * Update pg_database.datfrozenxid, and truncate pg_xact if possible. We
 	 * only need to do this once, not after each table.
 	 *
 	 * Even if we didn't vacuum anything, it may still be important to do
diff --git a/src/backend/storage/buffer/README b/src/backend/storage/buffer/README
index 248883f0dae..bc80777bb10 100644
--- a/src/backend/storage/buffer/README
+++ b/src/backend/storage/buffer/README
@@ -63,7 +63,7 @@ at about the same time would OR the same bits into the field, so there
 is little or no risk of conflicting update; what's more, if there did
 manage to be a conflict it would merely mean that one bit-update would
 be lost and need to be done again later.  These four bits are only hints
-(they cache the results of transaction status lookups in pg_clog), so no
+(they cache the results of transaction status lookups in pg_xact), so no
 great harm is done if they get reset to zero by conflicting updates.
 Note, however, that a tuple is frozen by setting both HEAP_XMIN_INVALID
 and HEAP_XMIN_COMMITTED; this is a critical update and accordingly requires
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index c724a0e9525..0f8f435faff 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -381,7 +381,7 @@ ProcArrayRemove(PGPROC *proc, TransactionId latestXid)
  * ProcArrayEndTransaction -- mark a transaction as no longer running
  *
  * This is used interchangeably for commit and abort cases.  The transaction
- * commit/abort must already be reported to WAL and pg_clog.
+ * commit/abort must already be reported to WAL and pg_xact.
  *
  * proc is currently always MyProc, but we pass it explicitly for flexibility.
  * latestXid is the latest Xid among the transaction's main XID and
@@ -1174,7 +1174,7 @@ TransactionIdIsInProgress(TransactionId xid)
 	 * At this point, we know it's either a subtransaction of one of the Xids
 	 * in xids[], or it's not running.  If it's an already-failed
 	 * subtransaction, we want to say "not running" even though its parent may
-	 * still be running.  So first, check pg_clog to see if it's been aborted.
+	 * still be running.  So first, check pg_xact to see if it's been aborted.
 	 */
 	xc_slow_answer_inc();
 
diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c
index 703bdcedaf4..519f3b68031 100644
--- a/src/backend/utils/time/tqual.c
+++ b/src/backend/utils/time/tqual.c
@@ -13,9 +13,9 @@
  * NOTE: When using a non-MVCC snapshot, we must check
  * TransactionIdIsInProgress (which looks in the PGXACT array)
  * before TransactionIdDidCommit/TransactionIdDidAbort (which look in
- * pg_clog).  Otherwise we have a race condition: we might decide that a
+ * pg_xact).  Otherwise we have a race condition: we might decide that a
  * just-committed transaction crashed, because none of the tests succeed.
- * xact.c is careful to record commit/abort in pg_clog before it unsets
+ * xact.c is careful to record commit/abort in pg_xact before it unsets
  * MyPgXact->xid in the PGXACT array.  That fixes that problem, but it
  * also means there is a window where TransactionIdIsInProgress and
  * TransactionIdDidCommit will both return true.  If we check only
@@ -29,7 +29,7 @@
  *
  * When using an MVCC snapshot, we rely on XidInMVCCSnapshot rather than
  * TransactionIdIsInProgress, but the logic is otherwise the same: do not
- * check pg_clog until after deciding that the xact is no longer in progress.
+ * check pg_xact until after deciding that the xact is no longer in progress.
  *
  *
  * Summary of visibility functions:
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 9b71e0042d8..e0c72fbb800 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -197,7 +197,6 @@ static const char *backend_options = "--single -F -O -j -c search_path=pg_catalo
 static const char *const subdirs[] = {
 	"global",
 	"pg_wal/archive_status",
-	"pg_clog",
 	"pg_commit_ts",
 	"pg_dynshmem",
 	"pg_notify",
@@ -214,6 +213,7 @@ static const char *const subdirs[] = {
 	"pg_tblspc",
 	"pg_stat",
 	"pg_stat_tmp",
+	"pg_xact",
 	"pg_logical",
 	"pg_logical/snapshots",
 	"pg_logical/mappings"
diff --git a/src/bin/pg_upgrade/exec.c b/src/bin/pg_upgrade/exec.c
index 91fa71728e8..cdce4be2113 100644
--- a/src/bin/pg_upgrade/exec.c
+++ b/src/bin/pg_upgrade/exec.c
@@ -338,11 +338,17 @@ check_data_dir(ClusterInfo *cluster)
 	check_single_dir(pg_data, "pg_tblspc");
 	check_single_dir(pg_data, "pg_twophase");
 
-	/* pg_xlog has been renamed to pg_wal in post-10 cluster */
+	/* pg_xlog has been renamed to pg_wal in v10 */
 	if (GET_MAJOR_VERSION(cluster->major_version) < 1000)
 		check_single_dir(pg_data, "pg_xlog");
 	else
 		check_single_dir(pg_data, "pg_wal");
+
+	/* pg_clog has been renamed to pg_xact in v10 */
+	if (GET_MAJOR_VERSION(cluster->major_version) < 1000)
+		check_single_dir(pg_data, "pg_clog");
+	else
+		check_single_dir(pg_data, "pg_xact");
 }
 
 
diff --git a/src/bin/pg_upgrade/pg_upgrade.c b/src/bin/pg_upgrade/pg_upgrade.c
index fc66d93dd6a..ca1aa5cbb80 100644
--- a/src/bin/pg_upgrade/pg_upgrade.c
+++ b/src/bin/pg_upgrade/pg_upgrade.c
@@ -48,7 +48,7 @@
 static void prepare_new_cluster(void);
 static void prepare_new_databases(void);
 static void create_new_objects(void);
-static void copy_clog_xlog_xid(void);
+static void copy_xact_xlog_xid(void);
 static void set_frozenxids(bool minmxid_only);
 static void setup(char *argv0, bool *live_check);
 static void cleanup(void);
@@ -115,7 +115,7 @@ main(int argc, char **argv)
 	 * Destructive Changes to New Cluster
 	 */
 
-	copy_clog_xlog_xid();
+	copy_xact_xlog_xid();
 
 	/* New now using xids of the old system */
 
@@ -376,17 +376,17 @@ remove_new_subdir(char *subdir, bool rmtopdir)
  * Copy the files from the old cluster into it
  */
 static void
-copy_subdir_files(char *subdir)
+copy_subdir_files(char *old_subdir, char *new_subdir)
 {
 	char		old_path[MAXPGPATH];
 	char		new_path[MAXPGPATH];
 
-	remove_new_subdir(subdir, true);
+	remove_new_subdir(new_subdir, true);
 
-	snprintf(old_path, sizeof(old_path), "%s/%s", old_cluster.pgdata, subdir);
-	snprintf(new_path, sizeof(new_path), "%s/%s", new_cluster.pgdata, subdir);
+	snprintf(old_path, sizeof(old_path), "%s/%s", old_cluster.pgdata, old_subdir);
+	snprintf(new_path, sizeof(new_path), "%s/%s", new_cluster.pgdata, new_subdir);
 
-	prep_status("Copying old %s to new server", subdir);
+	prep_status("Copying old %s to new server", old_subdir);
 
 	exec_prog(UTILITY_LOG_FILE, NULL, true,
 #ifndef WIN32
@@ -401,10 +401,16 @@ copy_subdir_files(char *subdir)
 }
 
 static void
-copy_clog_xlog_xid(void)
+copy_xact_xlog_xid(void)
 {
-	/* copy old commit logs to new data dir */
-	copy_subdir_files("pg_clog");
+	/*
+	 * Copy old commit logs to new data dir. pg_clog has been renamed to
+	 * pg_xact in post-10 clusters.
+	 */
+	copy_subdir_files(GET_MAJOR_VERSION(old_cluster.major_version) < 1000 ?
+					  "pg_clog" : "pg_xact",
+					  GET_MAJOR_VERSION(new_cluster.major_version) < 1000 ?
+					  "pg_clog" : "pg_xact");
 
 	/* set the next transaction id and epoch of the new cluster */
 	prep_status("Setting next transaction ID and epoch for new cluster");
@@ -434,8 +440,8 @@ copy_clog_xlog_xid(void)
 	if (old_cluster.controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER &&
 		new_cluster.controldata.cat_ver >= MULTIXACT_FORMATCHANGE_CAT_VER)
 	{
-		copy_subdir_files("pg_multixact/offsets");
-		copy_subdir_files("pg_multixact/members");
+		copy_subdir_files("pg_multixact/offsets", "pg_multixact/offsets");
+		copy_subdir_files("pg_multixact/members", "pg_multixact/members");
 
 		prep_status("Setting next multixact ID and offset for new cluster");
 
diff --git a/src/include/access/slru.h b/src/include/access/slru.h
index cf6edc3bdb3..722867d5d2b 100644
--- a/src/include/access/slru.h
+++ b/src/include/access/slru.h
@@ -76,7 +76,7 @@ typedef struct SlruSharedData
 	/*
 	 * Optional array of WAL flush LSNs associated with entries in the SLRU
 	 * pages.  If not zero/NULL, we must flush WAL before writing pages (true
-	 * for pg_clog, false for multixact, pg_subtrans, pg_notify).  group_lsn[]
+	 * for pg_xact, false for multixact, pg_subtrans, pg_notify).  group_lsn[]
 	 * has lsn_groups_per_page entries per buffer slot, each containing the
 	 * highest LSN known for a contiguous group of SLRU entries on that slot's
 	 * page.
@@ -119,7 +119,7 @@ typedef struct SlruCtlData
 	SlruShared	shared;
 
 	/*
-	 * This flag tells whether to fsync writes (true for pg_clog and multixact
+	 * This flag tells whether to fsync writes (true for pg_xact and multixact
 	 * stuff, false for pg_subtrans and pg_notify).
 	 */
 	bool		do_fsync;