Subject: [PATCH] Allow progress tracking of sub-commands.

From: Antonin Houska <[email-masked]>
Date: Mon, 4 May 2026 11:32:21 +0200

Some commands that support progress reporting run sub-commands, which also
report their progress. The typical case is that REPACK builds indexes. Instead
of disabling the progress tracking of the sub-commands, we can allow both the
"parent" command and the sub-command to report their progress at the same
time.
---
 contrib/file_fdw/file_fdw.c                   | 44 +++++++++++
 src/backend/commands/indexcmds.c              | 10 ++-
 src/backend/commands/repack.c                 | 14 +++-
 src/backend/utils/activity/backend_progress.c | 76 ++++++++++++++++---
 src/backend/utils/activity/backend_status.c   |  1 +
 src/backend/utils/adt/pgstatfuncs.c           |  9 ++-
 src/include/utils/backend_status.h            |  7 ++
 7 files changed, 142 insertions(+), 19 deletions(-)

diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 33a37d832ce..a60fb226320 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -36,6 +36,7 @@
 #include "optimizer/pathnode.h"
 #include "optimizer/planmain.h"
 #include "optimizer/restrictinfo.h"
+#include "utils/backend_status.h"
 #include "utils/acl.h"
 #include "utils/memutils.h"
 #include "utils/rel.h"
@@ -119,6 +120,16 @@ typedef struct FileFdwExecutionState
 	CopyFromState cstate;		/* COPY execution state */
 } FileFdwExecutionState;
 
+/*
+ * Since progress tracking of multiple COPY commands is not supported, the
+ * first file_fdw node of the plan needs to set pgstat_track_activities to
+ * false during startup, and the last active node needs to restore the
+ * original value during shutdown.
+ */
+static bool	save_pgstat_track_activities = false;
+static int	fdw_nodes = 0;
+static int	active_fdw_nodes = 0;
+
 /*
  * SQL functions
  */
@@ -616,6 +627,12 @@ fileGetForeignPlan(PlannerInfo *root,
 {
 	Index		scan_relid = baserel->relid;
 
+	/*
+	 * This seems to be the appropriate place to count file_fdw nodes in the
+	 * plan.
+	 */
+	fdw_nodes++;
+
 	/*
 	 * We have no native ability to evaluate restriction clauses, so we just
 	 * put all the scan_clauses into the plan node's qual list for the
@@ -695,6 +712,18 @@ fileBeginForeignScan(ForeignScanState *node, int eflags)
 	/* Add any options from the plan (currently only convert_selectively) */
 	options = list_concat(options, plan->fdw_private);
 
+	/*
+	 * Save the value of pgstat_track_activities if this is the first file_fdw
+	 * node of a plan containing multiple file_fdw nodes, and disable the
+	 * progress tracking. The monitoring infrastructure currently does not
+	 * support monitoring of multiple COPY commands.
+	 */
+	if (fdw_nodes > 1 && active_fdw_nodes++ == 0)
+	{
+		save_pgstat_track_activities = pgstat_track_activities;
+		pgstat_track_activities = false;
+	}
+
 	/*
 	 * Create CopyState from FDW options.  We always acquire all columns, so
 	 * as to match the expected ScanTupleSlot signature.
@@ -861,6 +890,21 @@ fileEndForeignScan(ForeignScanState *node)
 							  festate->cstate->num_errors));
 
 	EndCopyFrom(festate->cstate);
+
+
+	/*
+	 * Restore the value of pgstat_track_activities if this is the last
+	 * file_fdw node of a plan containing multiple file_fdw nodes, and enable
+	 * progress tracking if we disabled it earlier.
+	 */
+	if (active_fdw_nodes > 0)
+	{
+		if (--active_fdw_nodes == 0)
+		{
+			pgstat_track_activities = save_pgstat_track_activities;
+			fdw_nodes = 0;
+		}
+	}
 }
 
 /*
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 9ab74c8df0a..7280e64d118 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -3918,6 +3918,12 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 	 * more detailed comments.
 	 */
 
+	/*
+	 * XXX Is there a reason not to start progress reporting here? If it's ok,
+	 * then INDEX_CREATE_SUPPRESS_PROGRESS below is probably not needed.
+	 */
+	pgstat_progress_start_command(PROGRESS_COMMAND_CREATE_INDEX, relationOid);
+
 	foreach(lc, indexIds)
 	{
 		char	   *concurrentName;
@@ -3966,8 +3972,6 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		if (indexRel->rd_rel->relpersistence == RELPERSISTENCE_TEMP)
 			elog(ERROR, "cannot reindex a temporary table concurrently");
 
-		pgstat_progress_start_command(PROGRESS_COMMAND_CREATE_INDEX, idx->tableId);
-
 		progress_vals[0] = PROGRESS_CREATEIDX_COMMAND_REINDEX_CONCURRENTLY;
 		progress_vals[1] = 0;	/* initializing */
 		progress_vals[2] = idx->indexId;
@@ -4144,7 +4148,6 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		 * Update progress for the index to build, with the correct parent
 		 * table involved.
 		 */
-		pgstat_progress_start_command(PROGRESS_COMMAND_CREATE_INDEX, newidx->tableId);
 		progress_vals[0] = PROGRESS_CREATEIDX_COMMAND_REINDEX_CONCURRENTLY;
 		progress_vals[1] = PROGRESS_CREATEIDX_PHASE_BUILD;
 		progress_vals[2] = newidx->indexId;
@@ -4208,7 +4211,6 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		 * Update progress for the index to build, with the correct parent
 		 * table involved.
 		 */
-		pgstat_progress_start_command(PROGRESS_COMMAND_CREATE_INDEX, newidx->tableId);
 		progress_vals[0] = PROGRESS_CREATEIDX_COMMAND_REINDEX_CONCURRENTLY;
 		progress_vals[1] = PROGRESS_CREATEIDX_PHASE_VALIDATE_IDXSCAN;
 		progress_vals[2] = newidx->indexId;
diff --git a/src/backend/commands/repack.c b/src/backend/commands/repack.c
index 9d162957bc3..f360f37a9da 100644
--- a/src/backend/commands/repack.c
+++ b/src/backend/commands/repack.c
@@ -1937,6 +1937,7 @@ finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
 		pgstat_progress_update_param(PROGRESS_REPACK_PHASE,
 									 PROGRESS_REPACK_PHASE_REBUILD_INDEX);
 
+		reindex_params.options |= REINDEXOPT_REPORT_PROGRESS;
 		reindex_relation(NULL, OIDOldHeap, reindex_flags, &reindex_params);
 	}
 
@@ -3204,9 +3205,20 @@ build_new_indexes(Relation NewHeap, Relation OldHeap, List *OldIndexes)
 									 "repacknew",
 									 get_rel_namespace(ind->rd_index->indrelid),
 									 false);
-		newindex = index_create_copy(NewHeap, INDEX_CREATE_SUPPRESS_PROGRESS,
+
+		/*
+		 * We build the index on the new heap, but after the swap phase it'll
+		 * become an index on the old heap. It makes more sense to report the
+		 * progress this way. (The reporting API expects that both command and
+		 * subcommand deal with the same target.)
+		 */
+		pgstat_progress_start_command(PROGRESS_COMMAND_CREATE_INDEX,
+									  RelationGetRelid(OldHeap));
+		newindex = index_create_copy(NewHeap, 0,
 									 oldindex, ind->rd_rel->reltablespace,
 									 newName);
+		pgstat_progress_end_command();
+
 		copy_index_constraints(ind, newindex, RelationGetRelid(NewHeap));
 		result = lappend_oid(result, newindex);
 
diff --git a/src/backend/utils/activity/backend_progress.c b/src/backend/utils/activity/backend_progress.c
index b0359771de5..97965a6973c 100644
--- a/src/backend/utils/activity/backend_progress.c
+++ b/src/backend/utils/activity/backend_progress.c
@@ -22,6 +22,10 @@
  *
  * Set st_progress_command (and st_progress_command_target) in own backend
  * entry.  Also, zero-initialize st_progress_param array.
+ *
+ * If command has already been started, start a sub-command. Only parameters
+ * of the sub-command are updated until pgstat_progress_end_command() is
+ * called. (Target relation must be the same for both commands.)
  *-----------
  */
 void
@@ -33,9 +37,30 @@ pgstat_progress_start_command(ProgressCommandType cmdtype, Oid relid)
 		return;
 
 	PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
-	beentry->st_progress_command = cmdtype;
-	beentry->st_progress_command_target = relid;
-	MemSet(&beentry->st_progress_param, 0, sizeof(beentry->st_progress_param));
+	/* Sub-command should not be started w/o parent command. */
+	if (beentry->st_progress_command == PROGRESS_COMMAND_INVALID)
+	{
+		Assert(beentry->st_progress_command2 == PROGRESS_COMMAND_INVALID);
+
+		beentry->st_progress_command = cmdtype;
+		beentry->st_progress_command_target = relid;
+		MemSet(&beentry->st_progress_param, 0,
+			   sizeof(beentry->st_progress_param));
+	}
+	else if (beentry->st_progress_command2 == PROGRESS_COMMAND_INVALID)
+	{
+		Assert(beentry->st_progress_command != PROGRESS_COMMAND_INVALID);
+		Assert(beentry->st_progress_command_target == relid);
+
+		beentry->st_progress_command2 = cmdtype;
+		MemSet(&beentry->st_progress_param2, 0,
+			   sizeof(beentry->st_progress_param2));
+	}
+	else
+	{
+		/* Only one level of nesting is supported. */
+		Assert(false);
+	}
 	PGSTAT_END_WRITE_ACTIVITY(beentry);
 }
 
@@ -49,14 +74,20 @@ void
 pgstat_progress_update_param(int index, int64 val)
 {
 	volatile PgBackendStatus *beentry = MyBEEntry;
+	volatile int64	*params;
 
 	Assert(index >= 0 && index < PGSTAT_NUM_PROGRESS_PARAM);
+	Assert(beentry->st_progress_command != PROGRESS_COMMAND_INVALID ||
+		   beentry->st_progress_command2 != PROGRESS_COMMAND_INVALID);
 
 	if (!beentry || !pgstat_track_activities)
 		return;
 
+	params = (beentry->st_progress_command2 == PROGRESS_COMMAND_INVALID) ?
+		beentry->st_progress_param : beentry->st_progress_param2;
+
 	PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
-	beentry->st_progress_param[index] = val;
+	params[index] = val;
 	PGSTAT_END_WRITE_ACTIVITY(beentry);
 }
 
@@ -70,14 +101,20 @@ void
 pgstat_progress_incr_param(int index, int64 incr)
 {
 	volatile PgBackendStatus *beentry = MyBEEntry;
+	volatile int64	*params;
 
 	Assert(index >= 0 && index < PGSTAT_NUM_PROGRESS_PARAM);
+	Assert(beentry->st_progress_command != PROGRESS_COMMAND_INVALID ||
+		   beentry->st_progress_command2 != PROGRESS_COMMAND_INVALID);
 
 	if (!beentry || !pgstat_track_activities)
 		return;
 
+	params = (beentry->st_progress_command2 == PROGRESS_COMMAND_INVALID) ?
+		beentry->st_progress_param : beentry->st_progress_param2;
+
 	PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
-	beentry->st_progress_param[index] += incr;
+	params[index] += incr;
 	PGSTAT_END_WRITE_ACTIVITY(beentry);
 }
 
@@ -124,17 +161,24 @@ pgstat_progress_update_multi_param(int nparam, const int *index,
 {
 	volatile PgBackendStatus *beentry = MyBEEntry;
 	int			i;
+	volatile int64	*params;
 
 	if (!beentry || !pgstat_track_activities || nparam == 0)
 		return;
 
+	Assert(beentry->st_progress_command != PROGRESS_COMMAND_INVALID ||
+		   beentry->st_progress_command2 != PROGRESS_COMMAND_INVALID);
+
+	params = (beentry->st_progress_command2 == PROGRESS_COMMAND_INVALID) ?
+		beentry->st_progress_param : beentry->st_progress_param2;
+
 	PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
 
 	for (i = 0; i < nparam; ++i)
 	{
 		Assert(index[i] >= 0 && index[i] < PGSTAT_NUM_PROGRESS_PARAM);
 
-		beentry->st_progress_param[index[i]] = val[i];
+		params[index[i]] = val[i];
 	}
 
 	PGSTAT_END_WRITE_ACTIVITY(beentry);
@@ -144,7 +188,7 @@ pgstat_progress_update_multi_param(int nparam, const int *index,
  * pgstat_progress_end_command() -
  *
  * Reset st_progress_command (and st_progress_command_target) in own backend
- * entry.  This signals the end of the command.
+ * entry.  This signals the end of the command (or a sub-command).
  *-----------
  */
 void
@@ -155,11 +199,19 @@ pgstat_progress_end_command(void)
 	if (!beentry || !pgstat_track_activities)
 		return;
 
-	if (beentry->st_progress_command == PROGRESS_COMMAND_INVALID)
-		return;
-
 	PGSTAT_BEGIN_WRITE_ACTIVITY(beentry);
-	beentry->st_progress_command = PROGRESS_COMMAND_INVALID;
-	beentry->st_progress_command_target = InvalidOid;
+
+	if (beentry->st_progress_command2 != PROGRESS_COMMAND_INVALID)
+	{
+		Assert(beentry->st_progress_command != PROGRESS_COMMAND_INVALID);
+
+		beentry->st_progress_command2 = PROGRESS_COMMAND_INVALID;
+	}
+	else
+	{
+		beentry->st_progress_command = PROGRESS_COMMAND_INVALID;
+		beentry->st_progress_command_target = InvalidOid;
+	}
+
 	PGSTAT_END_WRITE_ACTIVITY(beentry);
 }
diff --git a/src/backend/utils/activity/backend_status.c b/src/backend/utils/activity/backend_status.c
index d685fc5cd87..15675992415 100644
--- a/src/backend/utils/activity/backend_status.c
+++ b/src/backend/utils/activity/backend_status.c
@@ -284,6 +284,7 @@ pgstat_bestart_initial(void)
 
 	lbeentry.st_state = STATE_STARTING;
 	lbeentry.st_progress_command = PROGRESS_COMMAND_INVALID;
+	lbeentry.st_progress_command2 = PROGRESS_COMMAND_INVALID;
 	lbeentry.st_progress_command_target = InvalidOid;
 	lbeentry.st_query_id = INT64CONST(0);
 	lbeentry.st_plan_id = INT64CONST(0);
diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
index 7a9dfa9ba3b..c2257d900af 100644
--- a/src/backend/utils/adt/pgstatfuncs.c
+++ b/src/backend/utils/adt/pgstatfuncs.c
@@ -314,6 +314,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 		Datum		values[PG_STAT_GET_PROGRESS_COLS] = {0};
 		bool		nulls[PG_STAT_GET_PROGRESS_COLS] = {0};
 		int			i;
+		volatile int64	*params;
 
 		local_beentry = pgstat_get_local_beentry_by_index(curr_backend);
 		beentry = &local_beentry->backendStatus;
@@ -322,7 +323,11 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 		 * Report values for only those backends which are running the given
 		 * command.
 		 */
-		if (beentry->st_progress_command != cmdtype)
+		if (beentry->st_progress_command == cmdtype)
+			params = beentry->st_progress_param;
+		else if (beentry->st_progress_command2 == cmdtype)
+			params = beentry->st_progress_param2;
+		else
 			continue;
 
 		/* Value available to all callers */
@@ -334,7 +339,7 @@ pg_stat_get_progress_info(PG_FUNCTION_ARGS)
 		{
 			values[2] = ObjectIdGetDatum(beentry->st_progress_command_target);
 			for (i = 0; i < PGSTAT_NUM_PROGRESS_PARAM; i++)
-				values[i + 3] = Int64GetDatum(beentry->st_progress_param[i]);
+				values[i + 3] = Int64GetDatum(params[i]);
 		}
 		else
 		{
diff --git a/src/include/utils/backend_status.h b/src/include/utils/backend_status.h
index a334e096e4a..f528f7abeec 100644
--- a/src/include/utils/backend_status.h
+++ b/src/include/utils/backend_status.h
@@ -169,6 +169,13 @@ typedef struct PgBackendStatus
 	Oid			st_progress_command_target;
 	int64		st_progress_param[PGSTAT_NUM_PROGRESS_PARAM];
 
+	/*
+	 * Some commands have a sub-command, e.g. REPACK (re)builds indexes. The
+	 * subcommands are supposed to have the same target.
+	 */
+	ProgressCommandType st_progress_command2;
+	int64		st_progress_param2[PGSTAT_NUM_PROGRESS_PARAM];
+
 	/* query identifier, optionally computed using post_parse_analyze_hook */
 	int64		st_query_id;
 
-- 
2.47.3

--=-=-=--