From d15d4066a4894a7a1b33b8e513323353bab6279f Mon Sep 17 00:00:00 2001
From: Shawn Reuland <shawn@stellar.org>
Date: Tue, 9 Jul 2024 13:07:49 -0700
Subject: [PATCH] #4911: added --parallel-job-size=100 default when datastore
 backend used

---
 services/horizon/cmd/db.go      |  9 +++-
 services/horizon/cmd/db_test.go | 80 +++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 services/horizon/cmd/db_test.go

diff --git a/services/horizon/cmd/db.go b/services/horizon/cmd/db.go
index 8a61038b92..a9e87aeca6 100644
--- a/services/horizon/cmd/db.go
+++ b/services/horizon/cmd/db.go
@@ -27,6 +27,8 @@ import (
 	hlog "github.com/stellar/go/support/log"
 )
 
+var runDBReingestRangeFn = runDBReingestRange
+
 var dbCmd = &cobra.Command{
 	Use:   "db [command]",
 	Short: "commands to manage horizon's postgres db",
@@ -390,13 +392,18 @@ var dbReingestRangeCmd = &cobra.Command{
 			}
 			storageBackendConfig.BufferedStorageBackendFactory = ledgerbackend.NewBufferedStorageBackend
 			storageBackendConfig.DataStoreFactory = datastore.NewDataStore
+			// when using buffered storage, performance observations have noted optimal parallel batch size
+			// of 100, apply that as default if the flag was absent.
+			if !viper.IsSet("parallel-job-size") {
+				parallelJobSize = 100
+			}
 		}
 
 		err := horizon.ApplyFlags(globalConfig, globalFlags, horizon.ApplyOptions{RequireCaptiveCoreFullConfig: false, AlwaysIngest: false})
 		if err != nil {
 			return err
 		}
-		return runDBReingestRange(
+		return runDBReingestRangeFn(
 			[]history.LedgerRange{{StartSequence: argsUInt32[0], EndSequence: argsUInt32[1]}},
 			reingestForce,
 			parallelWorkers,
diff --git a/services/horizon/cmd/db_test.go b/services/horizon/cmd/db_test.go
new file mode 100644
index 0000000000..1763d5ea29
--- /dev/null
+++ b/services/horizon/cmd/db_test.go
@@ -0,0 +1,80 @@
+package cmd
+
+import (
+	"testing"
+
+	horizon "github.com/stellar/go/services/horizon/internal"
+	"github.com/stellar/go/services/horizon/internal/db2/history"
+	"github.com/stellar/go/services/horizon/internal/ingest"
+	"github.com/stellar/go/support/db/dbtest"
+	"github.com/stretchr/testify/require"
+	"github.com/stretchr/testify/suite"
+)
+
+func TestDBCommandsTestSuite(t *testing.T) {
+	dbCmdSuite := &DBCommandsTestSuite{}
+	suite.Run(t, dbCmdSuite)
+}
+
+type DBCommandsTestSuite struct {
+	suite.Suite
+	dsn string
+}
+
+func (s *DBCommandsTestSuite) SetupSuite() {
+	runDBReingestRangeFn = func([]history.LedgerRange, bool, uint,
+		horizon.Config, ingest.StorageBackendConfig) error {
+		return nil
+	}
+
+	newDB := dbtest.Postgres(s.T())
+	s.dsn = newDB.DSN
+
+	RootCmd.SetArgs([]string{
+		"db", "migrate", "up", "--db-url", s.dsn})
+	require.NoError(s.T(), RootCmd.Execute())
+}
+
+func (s *DBCommandsTestSuite) TestDefaultParallelJobSizeForBufferedBackend() {
+	RootCmd.SetArgs([]string{
+		"db", "reingest", "range",
+		"--db-url", s.dsn,
+		"--network", "testnet",
+		"--parallel-workers", "2",
+		"--ledgerbackend", "datastore",
+		"--datastore-config", "../config.storagebackend.toml",
+		"2",
+		"10"})
+
+	require.NoError(s.T(), dbReingestRangeCmd.Execute())
+	require.Equal(s.T(), parallelJobSize, uint32(100))
+}
+
+func (s *DBCommandsTestSuite) TestDefaultParallelJobSizeForCaptiveBackend() {
+	RootCmd.SetArgs([]string{
+		"db", "reingest", "range",
+		"--db-url", s.dsn,
+		"--network", "testnet",
+		"--parallel-workers", "2",
+		"--ledgerbackend", "captive-core",
+		"2",
+		"10"})
+
+	require.NoError(s.T(), RootCmd.Execute())
+	require.Equal(s.T(), parallelJobSize, uint32(100_000))
+}
+
+func (s *DBCommandsTestSuite) TestUsesParallelJobSizeWhenSet() {
+	RootCmd.SetArgs([]string{
+		"db", "reingest", "range",
+		"--db-url", s.dsn,
+		"--network", "testnet",
+		"--parallel-workers", "2",
+		"--parallel-job-size", "5",
+		"--ledgerbackend", "captive-core",
+		"2",
+		"10"})
+
+	require.NoError(s.T(), RootCmd.Execute())
+	require.Equal(s.T(), parallelJobSize, uint32(5))
+}