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[PATCH v56 2/6] Add conditional lock feature to dshash
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* [PATCH v56 2/6] Add conditional lock feature to dshash
@ 2020-03-13 07:58  Kyotaro Horiguchi <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Kyotaro Horiguchi @ 2020-03-13 07:58 UTC (permalink / raw)

Dshash currently waits for lock unconditionally. It is inconvenient
when we want to avoid being blocked by other processes. This commit
adds alternative functions of dshash_find and dshash_find_or_insert
that allows immediate return on lock failure.
---
 src/backend/lib/dshash.c | 98 +++++++++++++++++++++-------------------
 src/include/lib/dshash.h |  3 ++
 2 files changed, 55 insertions(+), 46 deletions(-)

diff --git a/src/backend/lib/dshash.c b/src/backend/lib/dshash.c
index 29ad767618..f79b6de245 100644
--- a/src/backend/lib/dshash.c
+++ b/src/backend/lib/dshash.c
@@ -383,6 +383,10 @@ dshash_get_hash_table_handle(dshash_table *hash_table)
  * the caller must take care to ensure that the entry is not left corrupted.
  * The lock mode is either shared or exclusive depending on 'exclusive'.
  *
+ * If found is not NULL, *found is set to true if the key is found in the hash
+ * table. If the key is not found, *found is set to false and a pointer to a
+ * newly created entry is returned.
+ *
  * The caller must not lock a lock already.
  *
  * Note that the lock held is in fact an LWLock, so interrupts will be held on
@@ -392,36 +396,7 @@ dshash_get_hash_table_handle(dshash_table *hash_table)
 void *
 dshash_find(dshash_table *hash_table, const void *key, bool exclusive)
 {
-	dshash_hash hash;
-	size_t		partition;
-	dshash_table_item *item;
-
-	hash = hash_key(hash_table, key);
-	partition = PARTITION_FOR_HASH(hash);
-
-	Assert(hash_table->control->magic == DSHASH_MAGIC);
-	Assert(!hash_table->find_locked);
-
-	LWLockAcquire(PARTITION_LOCK(hash_table, partition),
-				  exclusive ? LW_EXCLUSIVE : LW_SHARED);
-	ensure_valid_bucket_pointers(hash_table);
-
-	/* Search the active bucket. */
-	item = find_in_bucket(hash_table, key, BUCKET_FOR_HASH(hash_table, hash));
-
-	if (!item)
-	{
-		/* Not found. */
-		LWLockRelease(PARTITION_LOCK(hash_table, partition));
-		return NULL;
-	}
-	else
-	{
-		/* The caller will free the lock by calling dshash_release_lock. */
-		hash_table->find_locked = true;
-		hash_table->find_exclusively_locked = exclusive;
-		return ENTRY_FROM_ITEM(item);
-	}
+	return dshash_find_extended(hash_table, key, exclusive, false, false, NULL);
 }
 
 /*
@@ -439,31 +414,60 @@ dshash_find_or_insert(dshash_table *hash_table,
 					  const void *key,
 					  bool *found)
 {
-	dshash_hash hash;
-	size_t		partition_index;
-	dshash_partition *partition;
+	return dshash_find_extended(hash_table, key, true, false, true, found);
+}
+
+
+/*
+ * Find the key in the hash table.
+ *
+ * "exclusive" is the lock mode in which the partition for the returned item
+ * is locked.  If "nowait" is true, the function immediately returns if
+ * required lock was not acquired.  "insert" indicates insert mode. In this
+ * mode new entry is inserted and set *found to false. *found is set to true if
+ * found. "found" must be non-null in this mode.
+ */
+void *
+dshash_find_extended(dshash_table *hash_table, const void *key,
+					 bool exclusive, bool nowait, bool insert, bool *found)
+{
+	dshash_hash hash = hash_key(hash_table, key);
+	size_t		partidx = PARTITION_FOR_HASH(hash);
+	dshash_partition *partition = &hash_table->control->partitions[partidx];
+	LWLockMode  lockmode = exclusive ? LW_EXCLUSIVE : LW_SHARED;
 	dshash_table_item *item;
 
-	hash = hash_key(hash_table, key);
-	partition_index = PARTITION_FOR_HASH(hash);
-	partition = &hash_table->control->partitions[partition_index];
-
-	Assert(hash_table->control->magic == DSHASH_MAGIC);
-	Assert(!hash_table->find_locked);
+	/* must be exclusive when insert allowed */
+	Assert(!insert || (exclusive && found != NULL));
 
 restart:
-	LWLockAcquire(PARTITION_LOCK(hash_table, partition_index),
-				  LW_EXCLUSIVE);
+	if (!nowait)
+		LWLockAcquire(PARTITION_LOCK(hash_table, partidx), lockmode);
+	else if (!LWLockConditionalAcquire(PARTITION_LOCK(hash_table, partidx),
+									   lockmode))
+		return NULL;
+
 	ensure_valid_bucket_pointers(hash_table);
 
 	/* Search the active bucket. */
 	item = find_in_bucket(hash_table, key, BUCKET_FOR_HASH(hash_table, hash));
 
 	if (item)
-		*found = true;
+	{
+		if (found)
+			*found = true;
+	}
 	else
 	{
-		*found = false;
+		if (found)
+			*found = false;
+
+		if (!insert)
+		{
+			/* The caller didn't told to add a new entry. */
+			LWLockRelease(PARTITION_LOCK(hash_table, partidx));
+			return NULL;
+		}
 
 		/* Check if we are getting too full. */
 		if (partition->count > MAX_COUNT_PER_PARTITION(hash_table))
@@ -479,7 +483,8 @@ restart:
 			 * Give up our existing lock first, because resizing needs to
 			 * reacquire all the locks in the right order to avoid deadlocks.
 			 */
-			LWLockRelease(PARTITION_LOCK(hash_table, partition_index));
+			LWLockRelease(PARTITION_LOCK(hash_table, partidx));
+
 			resize(hash_table, hash_table->size_log2 + 1);
 
 			goto restart;
@@ -493,12 +498,13 @@ restart:
 		++partition->count;
 	}
 
-	/* The caller must release the lock with dshash_release_lock. */
+	/* The caller will free the lock by calling dshash_release_lock. */
 	hash_table->find_locked = true;
-	hash_table->find_exclusively_locked = true;
+	hash_table->find_exclusively_locked = exclusive;
 	return ENTRY_FROM_ITEM(item);
 }
 
+
 /*
  * Remove an entry by key.  Returns true if the key was found and the
  * corresponding entry was removed.
diff --git a/src/include/lib/dshash.h b/src/include/lib/dshash.h
index a6ea377173..5b8114d041 100644
--- a/src/include/lib/dshash.h
+++ b/src/include/lib/dshash.h
@@ -91,6 +91,9 @@ extern void *dshash_find(dshash_table *hash_table,
 						 const void *key, bool exclusive);
 extern void *dshash_find_or_insert(dshash_table *hash_table,
 								   const void *key, bool *found);
+extern void *dshash_find_extended(dshash_table *hash_table, const void *key,
+								  bool exclusive, bool nowait, bool insert,
+								  bool *found);
 extern bool dshash_delete_key(dshash_table *hash_table, const void *key);
 extern void dshash_delete_entry(dshash_table *hash_table, void *entry);
 extern void dshash_release_lock(dshash_table *hash_table, void *entry);
-- 
2.27.0


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Content-Transfer-Encoding: 7bit
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 filename="v56-0003-Shared-memory-based-stats-collector.patch"



^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* [PATCH v44 05/10] Rename ChangeDest to ChangeContext, and absorb IndexInsertState
@ 2026-03-23 20:27  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Álvaro Herrera @ 2026-03-23 20:27 UTC (permalink / raw)

This makes the data structure simpler, as we only need a single struct
which can be passed down to all functions.

Also, the inititalization and release sequences are a bit simpler
and there's a single location in charge.
---
 src/backend/commands/cluster.c   | 307 ++++++++++++++-----------------
 src/tools/pgindent/typedefs.list |   2 +-
 2 files changed, 135 insertions(+), 174 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index b4acaeb6b93..b86e600af41 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -113,15 +113,6 @@ typedef struct
 static RelFileLocator repacked_rel_locator = {.relNumber = InvalidOid};
 static RelFileLocator repacked_rel_toast_locator = {.relNumber = InvalidOid};
 
-/*
- * Everything we need to call ExecInsertIndexTuples().
- */
-typedef struct IndexInsertState
-{
-	ResultRelInfo *rri;
-	EState	   *estate;
-} IndexInsertState;
-
 /* The WAL segment being decoded. */
 static XLogSegNo repack_current_segment = 0;
 
@@ -134,31 +125,27 @@ static XLogSegNo repack_current_segment = 0;
 /*
  * Information needed to apply concurrent data changes.
  */
-typedef struct ChangeDest
+typedef struct ChangeContext
 {
 	/* The relation the changes are applied to. */
-	Relation	rel;
-
-	/*
-	 * The following is needed to find the existing tuple if the change is
-	 * UPDATE or DELETE. 'ident_key' should have all the fields except for
-	 * 'sk_argument' initialized.
-	 */
-	Relation	ident_index;
-	ScanKey		ident_key;
-	int			ident_key_nentries;
+	Relation	cc_rel;
 
 	/* Needed to update indexes of rel_dst. */
-	IndexInsertState *iistate;
+	ResultRelInfo *cc_rri;
+	EState	   *cc_estate;
 
 	/*
-	 * Sequential number of the file containing the changes.
-	 *
-	 * TODO This field makes the structure name less descriptive. Should we
-	 * rename it, e.g. to ChangeApplyInfo?
+	 * Existing tuples to UPDATE and DELETE are located via this index. We
+	 * keep the scankey in partially initialized state to avoid repeated work.
+	 * sk_argument is completed on the fly.
 	 */
-	int			file_seq;
-} ChangeDest;
+	Relation	cc_ident_index;
+	ScanKey		cc_ident_key;
+	int			cc_ident_key_nentries;
+
+	/* Sequential number of the file containing the changes. */
+	int			cc_file_seq;
+} ChangeContext;
 
 /*
  * Layout of shared memory used for communication between backend and the
@@ -278,29 +265,27 @@ static bool repack_is_permitted_for_relation(RepackCommand cmd,
 static LogicalDecodingContext *repack_setup_logical_decoding(Oid relid);
 static bool decode_concurrent_changes(LogicalDecodingContext *ctx,
 									  DecodingWorkerShared *shared);
-static void apply_concurrent_changes(BufFile *file, ChangeDest *dest);
+static void apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt);
 static void apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-									IndexInsertState *iistate);
+									ChangeContext *chgcxt);
 static void apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 									TupleTableSlot *ondisk_tuple,
-									IndexInsertState *iistate);
+									ChangeContext *chgcxt);
 static void apply_concurrent_delete(Relation rel, TupleTableSlot *slot);
 static void restore_tuple(BufFile *file, Relation relation,
 						  TupleTableSlot *slot);
 static void adjust_toast_pointers(Relation relation, TupleTableSlot *dest,
-									   TupleTableSlot *src);
-static bool find_target_tuple(Relation rel, ChangeDest *dest,
+								  TupleTableSlot *src);
+static bool find_target_tuple(Relation rel, ChangeContext *chgcxt,
 							  TupleTableSlot *locator,
 							  TupleTableSlot *received);
 static void process_concurrent_changes(XLogRecPtr end_of_wal,
-									   ChangeDest *dest,
+									   ChangeContext *chgcxt,
 									   bool done);
-static IndexInsertState *get_index_insert_state(Relation relation,
-												Oid ident_index_id,
-												Relation *ident_index_p);
-static ScanKey build_identity_key(Oid ident_idx_oid, Relation rel_src,
-								  int *nentries);
-static void free_index_insert_state(IndexInsertState *iistate);
+static void initialize_change_context(ChangeContext *chgcxt,
+									  Relation relation,
+									  Oid ident_index_id);
+static void release_change_context(ChangeContext *chgcxt);
 static void cleanup_logical_decoding(LogicalDecodingContext *ctx);
 static void rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 											   Oid identIdx,
@@ -2871,13 +2856,13 @@ decode_concurrent_changes(LogicalDecodingContext *ctx,
  * Apply changes stored in 'file'.
  */
 static void
-apply_concurrent_changes(BufFile *file, ChangeDest *dest)
+apply_concurrent_changes(BufFile *file, ChangeContext *chgcxt)
 {
-	ConcurrentChangeKind	kind = '\0';
-	Relation	rel = dest->rel;
-	TupleTableSlot	*spilled_tuple;
-	TupleTableSlot	*old_update_tuple;
-	TupleTableSlot  *ondisk_tuple;
+	ConcurrentChangeKind kind = '\0';
+	Relation	rel = chgcxt->cc_rel;
+	TupleTableSlot *spilled_tuple;
+	TupleTableSlot *old_update_tuple;
+	TupleTableSlot *ondisk_tuple;
 	MemoryContext apply_cxt;
 	bool		have_old_tuple = false;
 
@@ -2924,12 +2909,12 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest)
 
 		/*
 		 * Just before an UPDATE or DELETE, we must update the command
-		 * counter, because the change could refer to a tuple that we
-		 * have just inserted; and before an INSERT, we have to do this
-		 * also if the previous command was either update or delete.
+		 * counter, because the change could refer to a tuple that we have
+		 * just inserted; and before an INSERT, we have to do this also if the
+		 * previous command was either update or delete.
 		 *
-		 * With this approach we don't spend so many CCIs for long
-		 * strings of only INSERTs, which can't affect one another.
+		 * With this approach we don't spend so many CCIs for long strings of
+		 * only INSERTs, which can't affect one another.
 		 */
 		if (kind == CHANGE_UPDATE_NEW || kind == CHANGE_DELETE ||
 			(kind == CHANGE_INSERT && (prevkind == CHANGE_UPDATE_NEW ||
@@ -2946,22 +2931,22 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest)
 
 		if (kind == CHANGE_INSERT)
 		{
-			apply_concurrent_insert(rel, spilled_tuple, dest->iistate);
+			apply_concurrent_insert(rel, spilled_tuple, chgcxt);
 		}
 		else if (kind == CHANGE_DELETE)
 		{
-			bool	found;
+			bool		found;
 
 			/* Find the tuple to be deleted */
-			found = find_target_tuple(rel, dest, spilled_tuple, ondisk_tuple);
+			found = find_target_tuple(rel, chgcxt, spilled_tuple, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "failed to find target tuple");
 			apply_concurrent_delete(rel, ondisk_tuple);
 		}
 		else if (kind == CHANGE_UPDATE_NEW)
 		{
-			TupleTableSlot	*key;
-			bool	found;
+			TupleTableSlot *key;
+			bool		found;
 
 			if (have_old_tuple)
 				key = old_update_tuple;
@@ -2969,20 +2954,20 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest)
 				key = spilled_tuple;
 
 			/* Find the tuple to be updated or deleted. */
-			found = find_target_tuple(rel, dest, key, ondisk_tuple);
+			found = find_target_tuple(rel, chgcxt, key, ondisk_tuple);
 			if (!found)
 				elog(ERROR, "failed to find target tuple");
 
 			/*
 			 * If 'tup' contains TOAST pointers, they point to the old
-			 * relation's toast. Copy the corresponding TOAST pointers for
-			 * the new relation from the existing tuple. (The fact that we
-			 * received a TOAST pointer here implies that the attribute
-			 * hasn't changed.)
+			 * relation's toast. Copy the corresponding TOAST pointers for the
+			 * new relation from the existing tuple. (The fact that we
+			 * received a TOAST pointer here implies that the attribute hasn't
+			 * changed.)
 			 */
 			adjust_toast_pointers(rel, spilled_tuple, ondisk_tuple);
 
-			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, dest->iistate);
+			apply_concurrent_update(rel, spilled_tuple, ondisk_tuple, chgcxt);
 
 			ExecClearTuple(old_update_tuple);
 			have_old_tuple = false;
@@ -3006,7 +2991,7 @@ apply_concurrent_changes(BufFile *file, ChangeDest *dest)
  */
 static void
 apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
-						IndexInsertState *iistate)
+						ChangeContext *chgcxt)
 {
 	List	   *recheck;
 
@@ -3019,8 +3004,8 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
 	 * action that already happened, we have no use for the recheck list of
 	 * indexes returned, so just free it.  XXX or maybe just leave it?
 	 */
-	recheck = ExecInsertIndexTuples(iistate->rri,
-									iistate->estate,
+	recheck = ExecInsertIndexTuples(chgcxt->cc_rri,
+									chgcxt->cc_estate,
 									0,
 									slot,
 									NIL, NULL);
@@ -3028,7 +3013,7 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
 
 	pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_INSERTED, 1);
 
-	ResetPerTupleExprContext(iistate->estate);
+	ResetPerTupleExprContext(chgcxt->cc_estate);
 }
 
 /*
@@ -3038,7 +3023,7 @@ apply_concurrent_insert(Relation rel, TupleTableSlot *slot,
 static void
 apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 						TupleTableSlot *ondisk_tuple,
-						IndexInsertState *iistate)
+						ChangeContext *chgcxt)
 {
 	LockTupleMode lockmode;
 	TM_FailureData tmfd;
@@ -3065,13 +3050,13 @@ apply_concurrent_update(Relation rel, TupleTableSlot *spilled_tuple,
 
 		if (update_indexes == TU_Summarizing)
 			flags |= EIIT_ONLY_SUMMARIZING;
-		recheck = ExecInsertIndexTuples(iistate->rri,
-										iistate->estate,
+		recheck = ExecInsertIndexTuples(chgcxt->cc_rri,
+										chgcxt->cc_estate,
 										flags,
 										spilled_tuple,
 										NIL, NULL);
 		list_free(recheck);
-		ResetPerTupleExprContext(iistate->estate);
+		ResetPerTupleExprContext(chgcxt->cc_estate);
 	}
 
 	pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_UPDATED, 1);
@@ -3135,19 +3120,19 @@ restore_tuple(BufFile *file, Relation relation, TupleTableSlot *slot)
 	ExecForceStoreHeapTuple(tup, slot, false);
 
 	/*
-	 * Next, read any attributes we stored separately into the tts_values array
-	 * elements expecting them, if any.  This matches store_change.
+	 * Next, read any attributes we stored separately into the tts_values
+	 * array elements expecting them, if any.  This matches store_change.
 	 */
 	BufFileReadExact(file, &natt_ext, sizeof(natt_ext));
 	if (natt_ext > 0)
 	{
-		TupleDesc desc = slot->tts_tupleDescriptor;
+		TupleDesc	desc = slot->tts_tupleDescriptor;
 
 		for (int i = 0; i < desc->natts; i++)
 		{
 			CompactAttribute *attr = TupleDescCompactAttr(desc, i);
-			varlena	   *varlen;
-			alignas(uint32) varlena	varhdr;
+			varlena    *varlen;
+			alignas(uint32) varlena varhdr;
 			void	   *value;
 			Size		varlensz;
 
@@ -3219,10 +3204,10 @@ adjust_toast_pointers(Relation relation, TupleTableSlot *dest, TupleTableSlot *s
  * not found, return false.
  */
 static bool
-find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator,
+find_target_tuple(Relation rel, ChangeContext *chgcxt, TupleTableSlot *locator,
 				  TupleTableSlot *retrieved)
 {
-	Form_pg_index idx = dest->ident_index->rd_index;
+	Form_pg_index idx = chgcxt->cc_ident_index->rd_index;
 	IndexScanDesc scan;
 	bool		retval;
 
@@ -3233,9 +3218,9 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator,
 	 *
 	 * Use the incoming tuple to finalize the scan key.
 	 */
-	for (int i = 0; i < dest->ident_key_nentries; i++)
+	for (int i = 0; i < chgcxt->cc_ident_key_nentries; i++)
 	{
-		ScanKey		entry = &dest->ident_key[i];
+		ScanKey		entry = &chgcxt->cc_ident_key[i];
 		AttrNumber	attno = idx->indkey.values[i];
 
 		entry->sk_argument = locator->tts_values[attno - 1];
@@ -3243,9 +3228,9 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator,
 	}
 
 	/* XXX no instrumentation for now */
-	scan = index_beginscan(rel, dest->ident_index, GetActiveSnapshot(),
-						   NULL, dest->ident_key_nentries, 0);
-	index_rescan(scan, dest->ident_key, dest->ident_key_nentries, NULL, 0);
+	scan = index_beginscan(rel, chgcxt->cc_ident_index, GetActiveSnapshot(),
+						   NULL, chgcxt->cc_ident_key_nentries, 0);
+	index_rescan(scan, chgcxt->cc_ident_key, chgcxt->cc_ident_key_nentries, NULL, 0);
 	retval = index_getnext_slot(scan, ForwardScanDirection, retrieved);
 	index_endscan(scan);
 
@@ -3260,7 +3245,7 @@ find_target_tuple(Relation rel, ChangeDest *dest, TupleTableSlot *locator,
  * are far too similar to each other.
  */
 static void
-process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done)
+process_concurrent_changes(XLogRecPtr end_of_wal, ChangeContext *chgcxt, bool done)
 {
 	DecodingWorkerShared *shared;
 	char		fname[MAXPGPATH];
@@ -3293,7 +3278,7 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done)
 		/*
 		 * Has the worker exported the file we are waiting for?
 		 */
-		if (last_exported == dest->file_seq)
+		if (last_exported == chgcxt->cc_file_seq)
 			break;
 
 		ConditionVariableSleep(&shared->cv, WAIT_EVENT_REPACK_WORKER_EXPORT);
@@ -3301,117 +3286,99 @@ process_concurrent_changes(XLogRecPtr end_of_wal, ChangeDest *dest, bool done)
 	ConditionVariableCancelSleep();
 
 	/* Open the file. */
-	DecodingWorkerFileName(fname, shared->relid, dest->file_seq);
+	DecodingWorkerFileName(fname, shared->relid, chgcxt->cc_file_seq);
 	file = BufFileOpenFileSet(&shared->sfs.fs, fname, O_RDONLY, false);
-	apply_concurrent_changes(file, dest);
+	apply_concurrent_changes(file, chgcxt);
 
 	BufFileClose(file);
 
 	/* Get ready for the next file. */
-	dest->file_seq++;
+	chgcxt->cc_file_seq++;
 }
 
 /*
- * Initialize IndexInsertState for index specified by ident_index_id.
- *
- * While doing that, also return the identity index in *ident_index_p.
+ * Initialize the ChangeContext struct for the given relation, with
+ * the given index as identity index.
  */
-static IndexInsertState *
-get_index_insert_state(Relation relation, Oid ident_index_id,
-					   Relation *ident_index_p)
+static void
+initialize_change_context(ChangeContext *chgcxt,
+						  Relation relation, Oid ident_index_id)
 {
-	EState	   *estate;
-	IndexInsertState *result;
-	Relation	ident_index = NULL;
+	chgcxt->cc_rel = relation;
 
-	result = (IndexInsertState *) palloc0(sizeof(IndexInsertState));
-	estate = CreateExecutorState();
+	/* Only initialize fields needed by ExecInsertIndexTuples(). */
+	chgcxt->cc_estate = CreateExecutorState();
 
-	result->rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
-	InitResultRelInfo(result->rri, relation, 0, 0, 0);
-	ExecOpenIndices(result->rri, false);
+	chgcxt->cc_rri = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
+	InitResultRelInfo(chgcxt->cc_rri, relation, 0, 0, 0);
+	ExecOpenIndices(chgcxt->cc_rri, false);
 
 	/*
-	 * Find the relcache entry of the identity index so that we spend no extra
-	 * effort to open / close it.
+	 * The table's relcache entry already has the relcache entry for the
+	 * identity index; find that.
 	 */
-	for (int i = 0; i < result->rri->ri_NumIndices; i++)
+	chgcxt->cc_ident_index = NULL;
+	for (int i = 0; i < chgcxt->cc_rri->ri_NumIndices; i++)
 	{
 		Relation	ind_rel;
 
-		ind_rel = result->rri->ri_IndexRelationDescs[i];
+		ind_rel = chgcxt->cc_rri->ri_IndexRelationDescs[i];
 		if (ind_rel->rd_id == ident_index_id)
-			ident_index = ind_rel;
+		{
+			chgcxt->cc_ident_index = ind_rel;
+			break;
+		}
 	}
-	if (ident_index == NULL)
+	if (chgcxt->cc_ident_index == NULL)
 		elog(ERROR, "failed to find identity index");
 
-	/* Only initialize fields needed by ExecInsertIndexTuples(). */
-	result->estate = estate;
-
-	*ident_index_p = ident_index;
-	return result;
-}
-
-/*
- * Build scan key to process logical changes.
- */
-static ScanKey
-build_identity_key(Oid ident_idx_oid, Relation rel_src, int *nentries)
-{
-	Relation	ident_idx_rel;
-	Form_pg_index ident_idx;
-	int			n,
-				i;
-	ScanKey		result;
-
-	Assert(OidIsValid(ident_idx_oid));
-	ident_idx_rel = index_open(ident_idx_oid, AccessShareLock);
-	ident_idx = ident_idx_rel->rd_index;
-	n = ident_idx->indnkeyatts;
-	result = (ScanKey) palloc(sizeof(ScanKeyData) * n);
-	for (i = 0; i < n; i++)
+	/* Set up for scanning said identity index */
 	{
-		ScanKey		entry;
-		Oid			opfamily,
-					opcintype,
-					opno,
-					opcode;
+		Form_pg_index indexForm;
 
-		entry = &result[i];
+		indexForm = chgcxt->cc_ident_index->rd_index;
+		chgcxt->cc_ident_key_nentries = indexForm->indnkeyatts;
+		chgcxt->cc_ident_key = (ScanKey) palloc_array(ScanKeyData, indexForm->indnkeyatts);
+		for (int i = 0; i < indexForm->indnkeyatts; i++)
+		{
+			ScanKey		entry;
+			Oid			opfamily,
+						opcintype,
+						opno,
+						opcode;
 
-		opfamily = ident_idx_rel->rd_opfamily[i];
-		opcintype = ident_idx_rel->rd_opcintype[i];
-		opno = get_opfamily_member(opfamily, opcintype, opcintype,
-								   BTEqualStrategyNumber);
+			entry = &chgcxt->cc_ident_key[i];
 
-		if (!OidIsValid(opno))
-			elog(ERROR, "failed to find = operator for type %u", opcintype);
+			opfamily = chgcxt->cc_ident_index->rd_opfamily[i];
+			opcintype = chgcxt->cc_ident_index->rd_opcintype[i];
+			opno = get_opfamily_member(opfamily, opcintype, opcintype,
+									   BTEqualStrategyNumber);
+			if (!OidIsValid(opno))
+				elog(ERROR, "failed to find = operator for type %u", opcintype);
+			opcode = get_opcode(opno);
+			if (!OidIsValid(opcode))
+				elog(ERROR, "failed to find = operator for operator %u", opno);
 
-		opcode = get_opcode(opno);
-		if (!OidIsValid(opcode))
-			elog(ERROR, "failed to find = operator for operator %u", opno);
-
-		/* Initialize everything but argument. */
-		ScanKeyInit(entry,
-					i + 1,
-					BTEqualStrategyNumber, opcode,
-					(Datum) NULL);
-		entry->sk_collation = ident_idx_rel->rd_indcollation[i];
+			/* Initialize everything but argument. */
+			ScanKeyInit(entry,
+						i + 1,
+						BTEqualStrategyNumber, opcode,
+						(Datum) NULL);
+			entry->sk_collation = chgcxt->cc_ident_index->rd_indcollation[i];
+		}
 	}
-	index_close(ident_idx_rel, AccessShareLock);
 
-	*nentries = n;
-	return result;
+	chgcxt->cc_file_seq = WORKER_FILE_SNAPSHOT + 1;
 }
 
 static void
-free_index_insert_state(IndexInsertState *iistate)
+release_change_context(ChangeContext *chgcxt)
 {
-	ExecCloseIndices(iistate->rri);
-	FreeExecutorState(iistate->estate);
-	pfree(iistate->rri);
-	pfree(iistate);
+	ExecCloseIndices(chgcxt->cc_rri);
+	FreeExecutorState(chgcxt->cc_estate);
+	/* XXX are these pfrees necessary? */
+	pfree(chgcxt->cc_rri);
+	pfree(chgcxt->cc_ident_key);
 }
 
 static void
@@ -3450,7 +3417,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 	Relation   *ind_refs,
 			   *ind_refs_p;
 	int			nind;
-	ChangeDest	chgdst;
+	ChangeContext chgcxt;
 
 	/* Like in cluster_rel(). */
 	lockmode_old = ShareUpdateExclusiveLock;
@@ -3496,12 +3463,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 				errmsg("identity index missing on the new relation"));
 
 	/* Gather information to apply concurrent changes. */
-	chgdst.rel = NewHeap;
-	chgdst.iistate = get_index_insert_state(NewHeap, ident_idx_new,
-											&chgdst.ident_index);
-	chgdst.ident_key = build_identity_key(ident_idx_new, OldHeap,
-										  &chgdst.ident_key_nentries);
-	chgdst.file_seq = WORKER_FILE_SNAPSHOT + 1;
+	initialize_change_context(&chgcxt, NewHeap, ident_idx_new);
 
 	/*
 	 * During testing, wait for another backend to perform concurrent data
@@ -3523,7 +3485,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 	 * hold AccessExclusiveLock. (Quite some amount of WAL could have been
 	 * written during the data copying and index creation.)
 	 */
-	process_concurrent_changes(end_of_wal, &chgdst, false);
+	process_concurrent_changes(end_of_wal, &chgcxt, false);
 
 	/*
 	 * Acquire AccessExclusiveLock on the table, its TOAST relation (if there
@@ -3608,7 +3570,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 	 * Apply the concurrent changes again. Indicate that the decoding worker
 	 * won't be needed anymore.
 	 */
-	process_concurrent_changes(end_of_wal, &chgdst, true);
+	process_concurrent_changes(end_of_wal, &chgcxt, true);
 
 	/* Remember info about rel before closing OldHeap */
 	relpersistence = OldHeap->rd_rel->relpersistence;
@@ -3659,8 +3621,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 	table_close(NewHeap, NoLock);
 
 	/* Cleanup what we don't need anymore. (And close the identity index.) */
-	pfree(chgdst.ident_key);
-	free_index_insert_state(chgdst.iistate);
+	release_change_context(&chgcxt);
 
 	/*
 	 * Swap the relations and their TOAST relations and TOAST indexes. This
@@ -3980,7 +3941,7 @@ repack_worker_internal(dsm_segment *seg)
 
 	for (;;)
 	{
-		bool	stop = decode_concurrent_changes(decoding_ctx, shared);
+		bool		stop = decode_concurrent_changes(decoding_ctx, shared);
 
 		if (stop)
 			break;
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 72f7c0b992b..12bfd50d25b 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -426,7 +426,7 @@ CatCacheHeader
 CatalogId
 CatalogIdMapEntry
 CatalogIndexState
-ChangeDest
+ChangeContext
 ChangeVarNodes_callback
 ChangeVarNodes_context
 ChannelName
-- 
2.47.3


--gwom7bl7ogtszo4k
Content-Type: text/x-diff; charset=utf-8
Content-Disposition: attachment;
	filename="v44-0006-rename-routines-on-the-logical-output-plugin-sid.patch"



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end of thread, other threads:[~2026-03-23 20:27 UTC | newest]

Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2020-03-13 07:58 [PATCH v56 2/6] Add conditional lock feature to dshash Kyotaro Horiguchi <[email protected]>
2026-03-23 20:27 [PATCH v44 05/10] Rename ChangeDest to ChangeContext, and absorb IndexInsertState Álvaro Herrera <[email protected]>

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