0001-Revert-VACUUM-ignore-indexing-operations-with-CONCUR.patch

From 8568ecb968b2a3a8b5b535546fee5bb1589db1d7 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Mon, 23 May 2022 14:25:22 +0900
Subject: [PATCH] Revert "VACUUM: ignore indexing operations with CONCURRENTLY"

This reverts commit d9d076222f5b94a85e0e318339cfc44b8f26022d.
---
 src/backend/storage/ipc/procarray.c | 41 ++++++-----------------------
 src/backend/utils/misc/guc.c        |  2 +-
 doc/src/sgml/ref/create_index.sgml  |  2 --
 doc/src/sgml/ref/reindex.sgml       |  2 --
 4 files changed, 9 insertions(+), 38 deletions(-)

diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index cd58c5faf0..21b468b5a8 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -1659,13 +1659,7 @@ TransactionIdIsActive(TransactionId xid)
  * relations that's not required, since only backends in my own database could
  * ever see the tuples in them. Also, we can ignore concurrently running lazy
  * VACUUMs because (a) they must be working on other tables, and (b) they
- * don't need to do snapshot-based lookups.  Similarly, for the non-catalog
- * horizon, we can ignore CREATE INDEX CONCURRENTLY and REINDEX CONCURRENTLY
- * when they are working on non-partial, non-expressional indexes, for the
- * same reasons and because they can't run in transaction blocks.  (They are
- * not possible to ignore for catalogs, because CIC and RC do some catalog
- * operations.)  Do note that this means that CIC and RC must use a lock level
- * that conflicts with VACUUM.
+ * don't need to do snapshot-based lookups.
  *
  * This also computes a horizon used to truncate pg_subtrans. For that
  * backends in all databases have to be considered, and concurrently running
@@ -1715,6 +1709,9 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 	bool		in_recovery = RecoveryInProgress();
 	TransactionId *other_xids = ProcGlobal->xids;
 
+	/* inferred after ProcArrayLock is released */
+	h->catalog_oldest_nonremovable = InvalidTransactionId;
+
 	LWLockAcquire(ProcArrayLock, LW_SHARED);
 
 	h->latest_completed = ShmemVariableCache->latestCompletedXid;
@@ -1734,7 +1731,6 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 
 		h->oldest_considered_running = initial;
 		h->shared_oldest_nonremovable = initial;
-		h->catalog_oldest_nonremovable = initial;
 		h->data_oldest_nonremovable = initial;
 
 		/*
@@ -1805,7 +1801,7 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 		if (statusFlags & (PROC_IN_VACUUM | PROC_IN_LOGICAL_DECODING))
 			continue;
 
-		/* shared tables need to take backends in all databases into account */
+		/* shared tables need to take backends in all database into account */
 		h->shared_oldest_nonremovable =
 			TransactionIdOlder(h->shared_oldest_nonremovable, xmin);
 
@@ -1833,25 +1829,11 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 			(statusFlags & PROC_AFFECTS_ALL_HORIZONS) ||
 			in_recovery)
 		{
-			/*
-			 * We can ignore this backend if it's running CREATE INDEX
-			 * CONCURRENTLY or REINDEX CONCURRENTLY on a "safe" index -- but
-			 * only on vacuums of user-defined tables.
-			 */
-			if (!(statusFlags & PROC_IN_SAFE_IC))
-				h->data_oldest_nonremovable =
-					TransactionIdOlder(h->data_oldest_nonremovable, xmin);
-
-			/* Catalog tables need to consider all backends in this db */
-			h->catalog_oldest_nonremovable =
-				TransactionIdOlder(h->catalog_oldest_nonremovable, xmin);
+			h->data_oldest_nonremovable =
+				TransactionIdOlder(h->data_oldest_nonremovable, xmin);
 		}
 	}
 
-	/* catalog horizon should never be later than data */
-	Assert(TransactionIdPrecedesOrEquals(h->catalog_oldest_nonremovable,
-										 h->data_oldest_nonremovable));
-
 	/*
 	 * If in recovery fetch oldest xid in KnownAssignedXids, will be applied
 	 * after lock is released.
@@ -1873,8 +1855,6 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 			TransactionIdOlder(h->shared_oldest_nonremovable, kaxmin);
 		h->data_oldest_nonremovable =
 			TransactionIdOlder(h->data_oldest_nonremovable, kaxmin);
-		h->catalog_oldest_nonremovable =
-			TransactionIdOlder(h->catalog_oldest_nonremovable, kaxmin);
 		/* temp relations cannot be accessed in recovery */
 	}
 	else
@@ -1901,9 +1881,6 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 		h->data_oldest_nonremovable =
 			TransactionIdRetreatedBy(h->data_oldest_nonremovable,
 									 vacuum_defer_cleanup_age);
-		h->catalog_oldest_nonremovable =
-			TransactionIdRetreatedBy(h->catalog_oldest_nonremovable,
-									 vacuum_defer_cleanup_age);
 		/* defer doesn't apply to temp relations */
 	}
 
@@ -1926,9 +1903,7 @@ ComputeXidHorizons(ComputeXidHorizonsResult *h)
 	h->shared_oldest_nonremovable =
 		TransactionIdOlder(h->shared_oldest_nonremovable,
 						   h->slot_catalog_xmin);
-	h->catalog_oldest_nonremovable =
-		TransactionIdOlder(h->catalog_oldest_nonremovable,
-						   h->slot_xmin);
+	h->catalog_oldest_nonremovable = h->data_oldest_nonremovable;
 	h->catalog_oldest_nonremovable =
 		TransactionIdOlder(h->catalog_oldest_nonremovable,
 						   h->slot_catalog_xmin);
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 8e9b71375c..5478762cdb 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2740,7 +2740,7 @@ static struct config_int ConfigureNamesInt[] =
 			NULL
 		},
 		&vacuum_defer_cleanup_age,
-		0, 0, 1000000,			/* see ComputeXidHorizons */
+		0, 0, 1000000,
 		NULL, NULL, NULL
 	},
 	{
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index 907324b93e..9ffcdc629e 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -861,8 +861,6 @@ Indexes:
    Like any long-running transaction, <command>CREATE INDEX</command> on a
    table can affect which tuples can be removed by concurrent
    <command>VACUUM</command> on any other table.
-   Excepted from this are operations with the <literal>CONCURRENTLY</literal>
-   option for indexes that are not partial and do not index any expressions.
   </para>
 
   <para>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index 36cb4a455b..336ca24b31 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -475,8 +475,6 @@ Indexes:
     Like any long-running transaction, <command>REINDEX</command> on a table
     can affect which tuples can be removed by concurrent
     <command>VACUUM</command> on any other table.
-    Excepted from this are operations with the <literal>CONCURRENTLY</literal>
-    option for indexes that are not partial and do not index any expressions.
    </para>
 
    <para>
-- 
2.36.1