From 5f7fa698dec2101a651552cefc39f3144c8f4545 Mon Sep 17 00:00:00 2001
From: Jeffrey Xiao <jeffrey.xiao1998@gmail.com>
Date: Tue, 21 May 2019 10:25:21 -0400
Subject: [PATCH] roachtest: revert not disabling merge queue

Roachtests need to remain compatible with 19.1 and having the merge
queue enabled when performing a split will throw an error.

Release note: None
---
 pkg/cmd/roachtest/election.go   |  2 ++
 pkg/workload/indexes/indexes.go | 15 +++++++++++++++
 pkg/workload/workload.go        | 16 ++++++++++++++++
 3 files changed, 33 insertions(+)

diff --git a/pkg/cmd/roachtest/election.go b/pkg/cmd/roachtest/election.go
index d5a246b721cb..a6880c553440 100644
--- a/pkg/cmd/roachtest/election.go
+++ b/pkg/cmd/roachtest/election.go
@@ -42,6 +42,8 @@ func registerElectionAfterRestart(r *registry) {
 			c.Run(ctx, c.Node(1), `./cockroach sql --insecure -e "
         CREATE DATABASE IF NOT EXISTS test;
         CREATE TABLE test.kv (k INT PRIMARY KEY, v INT);
+        -- Prevent the merge queue from immediately discarding our splits.
+        SET CLUSTER SETTING kv.range_merge.queue_enabled = false;
         ALTER TABLE test.kv SPLIT AT SELECT generate_series(0, 10000, 100)"`)
 
 			start := timeutil.Now()
diff --git a/pkg/workload/indexes/indexes.go b/pkg/workload/indexes/indexes.go
index 679963ddbcdd..9a51c3f5ecd1 100644
--- a/pkg/workload/indexes/indexes.go
+++ b/pkg/workload/indexes/indexes.go
@@ -96,6 +96,10 @@ func (w *indexes) Hooks() workload.Hooks {
 			return nil
 		},
 		PostLoad: func(sqlDB *gosql.DB) error {
+			// Prevent the merge queue from immediately discarding our splits.
+			if err := maybeDisableMergeQueue(sqlDB); err != nil {
+				return err
+			}
 			// Split at the beginning of each index so that as long as the
 			// table has a single index, all writes will be multi-range.
 			for i := 0; i < w.idxs; i++ {
@@ -109,6 +113,17 @@ func (w *indexes) Hooks() workload.Hooks {
 	}
 }
 
+func maybeDisableMergeQueue(sqlDB *gosql.DB) error {
+	var ok bool
+	if err := sqlDB.QueryRow(
+		`SELECT count(*) > 0 FROM [ SHOW ALL CLUSTER SETTINGS ] AS _ (v) WHERE v = 'kv.range_merge.queue_enabled'`,
+	).Scan(&ok); err != nil || !ok {
+		return err
+	}
+	_, err := sqlDB.Exec("SET CLUSTER SETTING kv.range_merge.queue_enabled = false")
+	return err
+}
+
 // Tables implements the Generator interface.
 func (w *indexes) Tables() []workload.Table {
 	// Construct the schema with all indexes.
diff --git a/pkg/workload/workload.go b/pkg/workload/workload.go
index 60c6a37df5f0..a194aa472c74 100644
--- a/pkg/workload/workload.go
+++ b/pkg/workload/workload.go
@@ -541,8 +541,24 @@ func Setup(
 	return size, nil
 }
 
+func maybeDisableMergeQueue(db *gosql.DB) error {
+	var ok bool
+	if err := db.QueryRow(
+		`SELECT count(*) > 0 FROM [ SHOW ALL CLUSTER SETTINGS ] AS _ (v) WHERE v = 'kv.range_merge.queue_enabled'`,
+	).Scan(&ok); err != nil || !ok {
+		return err
+	}
+	_, err := db.Exec("SET CLUSTER SETTING kv.range_merge.queue_enabled = false")
+	return err
+}
+
 // Split creates the range splits defined by the given table.
 func Split(ctx context.Context, db *gosql.DB, table Table, concurrency int) error {
+	// Prevent the merge queue from immediately discarding our splits.
+	if err := maybeDisableMergeQueue(db); err != nil {
+		return err
+	}
+
 	if table.Splits.NumBatches <= 0 {
 		return nil
 	}