From c5d53382782bf8decfd3f6d3edf8a8f4a5bfb385 Mon Sep 17 00:00:00 2001
From: Matthew Todd <todd@cockroachlabs.com>
Date: Mon, 24 Apr 2023 17:13:33 -0400
Subject: [PATCH] sqlstats: only include local region in statement_statistics

Part of #89949.

Addresses #98020.
Addresses #99563.

Related to cockroachdb/roachperf#129.
Related to #102170.

Previously, we attempted to record all the regions hit in a single
statement execution in the sqlstats tables, leaning on the
sqlAddressResolver to map traced nodeIDs to localities at execution
time.

While the sqlAddressResolver is generally non-blocking, the introduction
of this code did cause some of the multiregion "this query shouldn't
span regions" tests to start [flaking][] and it's more recently been
[implicated][] in a 2.5% performance regression.

Given that the probabilistic nature of the tracing meant that we
generally weren't capturing all the relevant nodeIDs anyway, it seems
like the most prudent thing to do here is take a step back and regroup.

In the short term, let's stop even trying to gather all these regions.
In the medium/long term, let's see if we can find a better approach.

[flaking]: https://github.com/cockroachdb/cockroach/issues/98020
[implicated]: https://github.com/cockroachdb/roachperf/pull/129

Release note: None
---
 .../multiregionccl/testdata/secondary_region  |  3 -
 pkg/sql/executor_statement_metrics.go         | 55 ++-----------------
 2 files changed, 5 insertions(+), 53 deletions(-)

diff --git a/pkg/ccl/multiregionccl/testdata/secondary_region b/pkg/ccl/multiregionccl/testdata/secondary_region
index 16a3c9fc94da..9fb454dab0cb 100644
--- a/pkg/ccl/multiregionccl/testdata/secondary_region
+++ b/pkg/ccl/multiregionccl/testdata/secondary_region
@@ -1,6 +1,3 @@
-skip issue-num=98020
-----
-
 new-cluster localities=us-east-1,us-east-1,us-west-1,us-west-1,us-central-1,us-central-1,us-central-1,eu-west-1,eu-west-1,eu-west-1
 ----
 
diff --git a/pkg/sql/executor_statement_metrics.go b/pkg/sql/executor_statement_metrics.go
index 24a86d271fe3..4b1a0f293ec6 100644
--- a/pkg/sql/executor_statement_metrics.go
+++ b/pkg/sql/executor_statement_metrics.go
@@ -12,9 +12,7 @@ package sql
 
 import (
 	"context"
-	"sort"
 	"strconv"
-	"sync"
 
 	"github.com/cockroachdb/cockroach/pkg/sql/appstatspb"
 	"github.com/cockroachdb/cockroach/pkg/sql/contentionpb"
@@ -22,7 +20,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/idxrecommendations"
 	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
 	"github.com/cockroachdb/cockroach/pkg/sql/sessionphase"
-	"github.com/cockroachdb/cockroach/pkg/sql/sqlinstance"
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlstats"
 	"github.com/cockroachdb/cockroach/pkg/util"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
@@ -189,7 +186,11 @@ func (ex *connExecutor) recordStatementSummary(
 	}
 
 	nodes := util.CombineUniqueInt64(getNodesFromPlanner(planner), []int64{nodeID})
-	regions := getRegionsForNodes(ctx, nodes, planner.DistSQLPlanner().sqlAddressResolver)
+
+	regions := []string{}
+	if region, ok := ex.server.cfg.Locality.Find("region"); ok {
+		regions = append(regions, region)
+	}
 
 	recordedStmtStats := sqlstats.RecordedStmtStats{
 		SessionID:            ex.sessionID,
@@ -327,49 +328,3 @@ func getNodesFromPlanner(planner *planner) []int64 {
 	}
 	return nodes
 }
-
-var regionsPool = sync.Pool{
-	New: func() interface{} {
-		return make(map[string]struct{})
-	},
-}
-
-func getRegionsForNodes(
-	ctx context.Context, nodeIDs []int64, resolver sqlinstance.AddressResolver,
-) []string {
-	if resolver == nil {
-		return nil
-	}
-
-	instances, err := resolver.GetAllInstances(ctx)
-	if err != nil {
-		return nil
-	}
-
-	regions := regionsPool.Get().(map[string]struct{})
-	defer func() {
-		for region := range regions {
-			delete(regions, region)
-		}
-		regionsPool.Put(regions)
-	}()
-
-	for _, instance := range instances {
-		for _, node := range nodeIDs {
-			// TODO(todd): Using int64 for nodeIDs was inappropriate, see #95088.
-			if int32(instance.InstanceID) == int32(node) {
-				if region, ok := instance.Locality.Find("region"); ok {
-					regions[region] = struct{}{}
-				}
-				break
-			}
-		}
-	}
-
-	result := make([]string, 0, len(regions))
-	for region := range regions {
-		result = append(result, region)
-	}
-	sort.Strings(result)
-	return result
-}