[#18822] YSQL: Re-enable feature to skip redundant index updates

Summary:
Timeline:

D34040 introduced an optimization to skip redundant index updates and foreign key checks.
D37746 gated this feature behind a preview flag (feature is OFF by default) named yb_update_optimization_infra.
D37749 introduced a feature enablement flag ysql_yb_skip_redundant_update_ops, and promoted the above preview flag to an auto flag.
D40300 turned OFF the feature via the enablement flag ysql_yb_skip_redundant_update_ops due to the bug GH-25075.
D40404 fixed the above bug.

This revision turns ON the feature by default by turning ON the feature enablement flag ysql_yb_skip_redundant_update_ops.
This reverts commit 0529391 (D40300).
Jira: DB-7701

Test Plan: Run Jenkins

Reviewers: amartsinchyk, smishra

Reviewed By: amartsinchyk

Subscribers: ybase, yql

Tags: #jenkins-ready

Differential Revision: https://phorge.dev.yugabyte.com/D40649

java/yb-pgsql/src/test/java/org/yb/pgsql/TestPgExplainAnalyzeModifyTable.java

@@ -250,7 +250,6 @@ public void testOnConflict() throws Exception {
                 .plans(resultNodeChecker
                     .storageTableReadRequests(Checkers.equal(1))
                     .storageTableWriteRequests(Checkers.equal(1))
-                    .storageIndexWriteRequests(Checkers.equal(TEST_NUM_SEC_INDEXES))
                     .build())
                 .build())
             .storageFlushRequests(Checkers.equal(1))
@@ -304,15 +303,15 @@ public void testOnConflict() throws Exception {
     {
         Checker checker = topLevelChecker
             .plan(insertNodeChecker
-                .plans(resultNodeChecker
+                .plans(makePlanBuilder()
+                    .nodeType(NODE_RESULT)
                     .storageTableReadRequests(Checkers.equal(1))
                     .storageTableWriteRequests(Checkers.equal(1))
-                    .storageIndexWriteRequests(Checkers.equal(TEST_NUM_SEC_INDEXES * 2))
                     .build())
                 .build())
-            .storageFlushRequests(Checkers.equal(2))
+            .storageFlushRequests(Checkers.equal(1))
             .storageReadRequests(Checkers.equal(1))
-            .storageWriteRequests(Checkers.equal((TEST_NUM_SEC_INDEXES * 2) + 1))
+            .storageWriteRequests(Checkers.equal(1))
             .build();
 
         testExplain(String.format(insertWithOnConflict, TEST_TABLE, "(1, 1, 1, 1, 1)", "k",

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

@@ -2997,7 +2997,7 @@ static struct config_bool ConfigureNamesBool[] =
 			GUC_NOT_IN_SAMPLE
 		},
 		&yb_update_optimization_options.is_enabled,
-		false,
+		true,
 		NULL, NULL, NULL
 	},
 

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

@@ -1639,7 +1639,7 @@ bool yb_enable_inplace_index_update = true;
 
 YBUpdateOptimizationOptions yb_update_optimization_options = {
 	.has_infra = true,
-	.is_enabled = false,
+	.is_enabled = true,
 	.num_cols_to_compare = 50,
 	.max_cols_size_to_compare = 10 * 1024
 };

src/yb/common/common_flags.cc

@@ -230,7 +230,7 @@ DEFINE_RUNTIME_AUTO_PG_FLAG(bool, yb_update_optimization_infra, kLocalPersisted,
                             "(but not limited to) skipping redundant secondary index updates "
                             "and redundant constraint checks.");
 
-DEFINE_RUNTIME_PG_FLAG(bool, yb_skip_redundant_update_ops, false,
+DEFINE_RUNTIME_PG_FLAG(bool, yb_skip_redundant_update_ops, true,
                        "Enables the comparison of old and new values of columns specified in the "
                        "SET clause of YSQL UPDATE queries to skip redundant secondary index "
                        "updates and redundant constraint checks.");