sql: speed up recently added TestTruncateLarge

We just saw a timeout in tests where 15m limit was exceeded because more
than 11m were consumed by TestTruncateLarge. In order to speed up the
test, this commit reduces the number of tables affected as well as
splits up two sub-tests into separate tests (hoping that they will end
up in different shards).

Release note: None

Author: yuzefovich

pkg/sql/drop_test.go

@@ -1557,42 +1557,52 @@ func TestDropLargeDatabaseWithDeclarativeSchemaChanger(t *testing.T) {
 func TestTruncateLarge(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
-	skip.UnderDuress(t, "truncating a large number of tables")
+	testTruncateLarge(t, true /* batchLimitSet */)
+}
 
-	testutils.RunTrueAndFalse(t, "batch limit set", func(t *testing.T, batchLimitSet bool) {
-		ctx := context.Background()
-		srv, conn, _ := serverutils.StartServer(t, base.TestServerArgs{})
-		defer srv.Stopper().Stop(ctx)
-		sqlDB := sqlutils.MakeSQLRunner(conn)
-		createCommand := strings.Builder{}
-		truncateCommand := strings.Builder{}
-		systemDB := sqlutils.MakeSQLRunner(srv.SystemLayer().SQLConn(t))
-		systemDB.Exec(t, "SET CLUSTER SETTING kv.raft.command.max_size='5m'")
-		if batchLimitSet {
-			sqlDB.Exec(t, "SET CLUSTER SETTING sql.schema_changer.batch_flush_threshold_size='2m'")
-		}
-		// Generate the truncate and create table commands.
-		const numTables = 500
-		truncateCommand.WriteString("TRUNCATE TABLE ")
-		for i := range numTables {
-			createCommand.WriteString(fmt.Sprintf("CREATE TABLE t%d (a INT PRIMARY KEY, j INT, k INT, INDEX (j), INDEX (k), UNIQUE (j, k));\n", i))
-			truncateCommand.WriteString(fmt.Sprintf("t%d", i))
-			if i != numTables-1 {
-				truncateCommand.WriteString(", ")
-			}
-		}
-		// Execute the create commands first.
-		sqlDB.Exec(t, createCommand.String())
+// TestTruncateLargeErr verifies that an error is returned if the batch limit is
+// effectively not set.
+func TestTruncateLargeErr(t *testing.T) {
+	defer leaktest.AfterTest(t)()
+	defer log.Scope(t).Close(t)
+	testTruncateLarge(t, false /* batchLimitSet */)
+}
 
-		// The default limit is larger than our reduced raft command size, so if the
-		// limit is not modified, the truncate command will fail.
-		if batchLimitSet {
-			sqlDB.Exec(t, truncateCommand.String())
-		} else {
-			sqlDB.ExpectErr(t, "command is too large", truncateCommand.String())
-		}
+func testTruncateLarge(t *testing.T, batchLimitSet bool) {
+	skip.UnderDuress(t, "truncating a large number of tables")
+
+	srv, conn, _ := serverutils.StartServer(t, base.TestServerArgs{
+		SQLMemoryPoolSize: 1 << 30, /* 1 GiB */
 	})
+	defer srv.Stopper().Stop(context.Background())
+	sqlDB := sqlutils.MakeSQLRunner(conn)
+	createCommand := strings.Builder{}
+	truncateCommand := strings.Builder{}
+	systemDB := sqlutils.MakeSQLRunner(srv.SystemLayer().SQLConn(t))
+	systemDB.Exec(t, "SET CLUSTER SETTING kv.raft.command.max_size='4.1MiB'")
+	if batchLimitSet {
+		sqlDB.Exec(t, "SET CLUSTER SETTING sql.schema_changer.batch_flush_threshold_size='1.8MiB'")
+	}
+	// Generate the truncate and create table commands.
+	const numTables = 340
+	truncateCommand.WriteString("TRUNCATE TABLE ")
+	for i := range numTables {
+		createCommand.WriteString(fmt.Sprintf("CREATE TABLE t%d (a INT PRIMARY KEY, j INT, k INT, INDEX (j), INDEX (k), UNIQUE (j, k));\n", i))
+		truncateCommand.WriteString(fmt.Sprintf("t%d", i))
+		if i != numTables-1 {
+			truncateCommand.WriteString(", ")
+		}
+	}
+	// Execute the create commands first.
+	sqlDB.Exec(t, createCommand.String())
 
+	// The default limit is larger than our reduced raft command size, so if the
+	// limit is not modified, the truncate command will fail.
+	if batchLimitSet {
+		sqlDB.Exec(t, truncateCommand.String())
+	} else {
+		sqlDB.ExpectErr(t, "command is too large", truncateCommand.String())
+	}
 }
 
 func BenchmarkDropLargeDatabaseWithGenerateTestObjects(b *testing.B) {