[BACKPORT pg15-cherrypicks][#22519] YSQL: Substitute YBSetRowLockPoli…

…cy function with YBGetDocDBWaitPolicy

Summary:
Original commit: 7f59bd8 / D38003
Auxiliary diff to fix `TODO` section to simplify the `YBSetRowLockPolicy` function usage by substituting it with the `YBGetDocDBWaitPolicy` function.

The purpose of this diff is to reduce changes in main diff for the #22519 issue (https://phorge.dev.yugabyte.com/D37821)
Jira: DB-11445

Merge:
  src/postgres/src/backend/executor/nodeYbSeqscan.c - trivial conflict between YB pg15 71dc8d0 and YB master 7f59bd8 in the YbSeqNext function

Test Plan: Jenkins

Reviewers: jason, tfoucher

Reviewed By: jason

Subscribers: yql

Tags: #jenkins-ready

Differential Revision: https://phorge.dev.yugabyte.com/D38071

src/postgres/src/backend/access/yb_access/yb_scan.c

@@ -3757,15 +3757,6 @@ YbFetchHeapTuple(Relation relation, Datum ybctid, HeapTuple* tuple)
 	return has_data;
 }
 
-// TODO: Substitute the YBSetRowLockPolicy with this function
-static int
-YBCGetRowLockPolicy(LockWaitPolicy pg_wait_policy)
-{
-	int docdb_wait_policy;
-	YBSetRowLockPolicy(&docdb_wait_policy, pg_wait_policy);
-	return docdb_wait_policy;
-}
-
 /*
  * The return value of this function depends on whether we are batching or not.
  * Currently, batching is enabled if the GUC yb_explicit_row_locking_batch_size > 1
@@ -3779,7 +3770,7 @@ YBCLockTuple(
 	Relation relation, Datum ybctid, RowMarkType mode,
 	LockWaitPolicy pg_wait_policy, EState* estate)
 {
-	int docdb_wait_policy = YBCGetRowLockPolicy(pg_wait_policy);
+	const int docdb_wait_policy = YBGetDocDBWaitPolicy(pg_wait_policy);
 	const YBCPgExplicitRowLockParams lock_params = {
 		.rowmark = mode,
 		.pg_wait_policy = pg_wait_policy,
@@ -3788,8 +3779,8 @@ YBCLockTuple(
 	const Oid relfile_oid = YbGetRelfileNodeId(relation);
 	const Oid db_oid = YBCGetDatabaseOid(relation);
 
-	if (yb_explicit_row_locking_batch_size > 1
-	    && lock_params.pg_wait_policy != LockWaitSkip)
+	if (yb_explicit_row_locking_batch_size > 1 &&
+		lock_params.pg_wait_policy != LockWaitSkip)
 	{
 		// TODO: Error message requires conversion
 		HandleYBStatus(YBCAddExplicitRowLockIntent(

src/postgres/src/backend/executor/nodeIndexscan.c

@@ -190,8 +190,8 @@ IndexNext(IndexScanState *node)
 				if (erm->markType != ROW_MARK_REFERENCE && erm->markType != ROW_MARK_COPY) {
 					scandesc->yb_exec_params->rowmark = erm->markType;
 					scandesc->yb_exec_params->pg_wait_policy = erm->waitPolicy;
-					YBSetRowLockPolicy(&scandesc->yb_exec_params->docdb_wait_policy,
-									   erm->waitPolicy);
+					scandesc->yb_exec_params->docdb_wait_policy =
+						YBGetDocDBWaitPolicy(erm->waitPolicy);
 				}
 			}
 		}

src/postgres/src/backend/executor/nodeYbSeqscan.c

@@ -153,9 +153,7 @@ YbSeqNext(YbSeqScanState *node)
 
 				ybScan->exec_params->rowmark = erm->markType;
 				ybScan->exec_params->pg_wait_policy = erm->waitPolicy;
-				YBSetRowLockPolicy(
-					&ybScan->exec_params->docdb_wait_policy,
-					erm->waitPolicy);
+				ybScan->exec_params->docdb_wait_policy = YBGetDocDBWaitPolicy(erm->waitPolicy);
 			}
 		}
 	}

src/postgres/src/backend/executor/ybc_fdw.c

@@ -370,8 +370,8 @@ ybcBeginForeignScan(ForeignScanState *node, int eflags)
 			{
 				ybc_state->exec_params->rowmark = erm->markType;
 				ybc_state->exec_params->pg_wait_policy = erm->waitPolicy;
-				YBSetRowLockPolicy(&ybc_state->exec_params->docdb_wait_policy,
-								   erm->waitPolicy);
+				ybc_state->exec_params->docdb_wait_policy =
+					YBGetDocDBWaitPolicy(erm->waitPolicy);
 			}
 		}
 	}

src/postgres/src/backend/utils/misc/pg_yb_utils.c

@@ -4669,8 +4669,10 @@ uint64_t YbGetSharedCatalogVersion()
 	return version;
 }
 
-void YBSetRowLockPolicy(int *docdb_wait_policy, LockWaitPolicy pg_wait_policy)
+LockWaitPolicy YBGetDocDBWaitPolicy(LockWaitPolicy pg_wait_policy)
 {
+	LockWaitPolicy result = pg_wait_policy;
+
 	if (XactIsoLevel == XACT_REPEATABLE_READ && pg_wait_policy == LockWaitError)
 	{
 		/* The user requested NOWAIT, which isn't allowed in RR. */
@@ -4689,14 +4691,10 @@ void YBSetRowLockPolicy(int *docdb_wait_policy, LockWaitPolicy pg_wait_policy)
 						  "(GH issue #11761)",
 						  pg_wait_policy == LockWaitSkip ? "SKIP LOCKED" : "NO WAIT");
 
-		*docdb_wait_policy = LockWaitBlock;
-	}
-	else
-	{
-		*docdb_wait_policy = pg_wait_policy;
+		result = LockWaitBlock;
 	}
 
-	if (*docdb_wait_policy == LockWaitBlock && !YBIsWaitQueueEnabled())
+	if (result == LockWaitBlock && !YBIsWaitQueueEnabled())
 	{
 		/*
 		 * If wait-queues are not enabled, we default to the "Fail-on-Conflict" policy which is
@@ -4705,9 +4703,10 @@ void YBSetRowLockPolicy(int *docdb_wait_policy, LockWaitPolicy pg_wait_policy)
 		 * semantics but to Fail-on-Conflict semantics).
 		 */
 		elog(DEBUG1, "Falling back to LockWaitError since wait-queues are not enabled");
-		*docdb_wait_policy = LockWaitError;
+		result = LockWaitError;
 	}
-	elog(DEBUG2, "docdb_wait_policy=%d pg_wait_policy=%d", *docdb_wait_policy, pg_wait_policy);
+	elog(DEBUG2, "docdb_wait_policy=%d pg_wait_policy=%d", result, pg_wait_policy);
+	return result;
 }
 
 uint32_t YbGetNumberOfDatabases()

src/postgres/src/include/pg_yb_utils.h

@@ -1012,19 +1012,21 @@ bool YbCatalogVersionTableInPerdbMode();
  * This function maps the user intended row-level lock policy i.e., "pg_wait_policy" of
  * type enum LockWaitPolicy to the "docdb_wait_policy" of type enum WaitPolicy as defined in
  * common.proto.
+ * Note: enum WaitPolicy values are equal to enum LockWaitPolicy.
+ *       That is why function maps enum LockWaitPolicy into enum LockWaitPolicy.
  *
  * The semantics of the WaitPolicy enum differ slightly from those of the traditional LockWaitPolicy
  * in Postgres, as explained in common.proto. This is for historical reasons. WaitPolicy in
  * common.proto was created as a copy of LockWaitPolicy to be passed to the Tserver to help in
  * appropriate conflict-resolution steps for the different row-level lock policies.
  *
- * In isolation level SERIALIZABLE, this function sets docdb_wait_policy to WAIT_BLOCK as
+ * In isolation level SERIALIZABLE, this function returns WAIT_BLOCK as
  * this is the only policy currently supported for SERIALIZABLE.
  *
  * However, if wait queues aren't enabled in the following cases:
  *  * Isolation level SERIALIZABLE
  *  * The user requested LockWaitBlock in another isolation level
- * this function sets docdb_wait_policy to WAIT_ERROR (which actually uses the "Fail on Conflict"
+ * this function returns WAIT_ERROR (which actually uses the "Fail on Conflict"
  * conflict management policy instead of "no wait" semantics, as explained in "enum WaitPolicy" in
  * common.proto).
  *
@@ -1034,7 +1036,7 @@ bool YbCatalogVersionTableInPerdbMode();
  * 2. In isolation level REPEATABLE READ for a pg_wait_policy of LockWaitError because NOWAIT
  *    is not supported.
  */
-void YBSetRowLockPolicy(int *docdb_wait_policy, LockWaitPolicy pg_wait_policy);
+LockWaitPolicy YBGetDocDBWaitPolicy(LockWaitPolicy pg_wait_policy);
 
 const char *yb_fetch_current_transaction_priority(void);