fix(sims): OOM at sim-multi-seed-long run (#21503)

testutils/sims/runner.go

@@ -3,6 +3,7 @@ package sims
 import (
 	"fmt"
 	"io"
+	"os"
 	"path/filepath"
 	"testing"
 
@@ -50,6 +51,7 @@ type SimulationApp interface {
 	SetNotSigverifyTx()
 	GetBaseApp() *baseapp.BaseApp
 	TxConfig() client.TxConfig
+	Close() error
 }
 
 // Run is a helper function that runs a simulation test with the given parameters.
@@ -114,7 +116,6 @@ func RunWithSeeds[T SimulationApp](
 				runLogger = log.NewTestLoggerInfo(t)
 			}
 			runLogger = runLogger.With("seed", tCfg.Seed)
-
 			app := testInstance.App
 			stateFactory := setupStateFactory(app)
 			simParams, err := simulation.SimulateFromSeedX(
@@ -124,7 +125,7 @@ func RunWithSeeds[T SimulationApp](
 				app.GetBaseApp(),
 				stateFactory.AppStateFn,
 				simtypes.RandomAccounts, // Replace with own random account function if using keys other than secp256k1
-				simtestutil.SimulationOperations(app, stateFactory.Codec, tCfg, testInstance.App.TxConfig()),
+				simtestutil.SimulationOperations(app, stateFactory.Codec, tCfg, app.TxConfig()),
 				stateFactory.BlockedAddr,
 				tCfg,
 				stateFactory.Codec,
@@ -134,12 +135,13 @@ func RunWithSeeds[T SimulationApp](
 			require.NoError(t, err)
 			err = simtestutil.CheckExportSimulation(app, tCfg, simParams)
 			require.NoError(t, err)
-			if tCfg.Commit {
+			if tCfg.Commit && tCfg.DBBackend == "goleveldb" {
 				simtestutil.PrintStats(testInstance.DB.(*dbm.GoLevelDB))
 			}
 			for _, step := range postRunActions {
 				step(t, testInstance)
 			}
+			require.NoError(t, app.Close())
 		})
 	}
 }
@@ -173,6 +175,8 @@ func NewSimulationAppInstance[T SimulationApp](
 ) TestInstance[T] {
 	t.Helper()
 	workDir := t.TempDir()
+	require.NoError(t, os.Mkdir(filepath.Join(workDir, "data"), 0o755))
+
 	dbDir := filepath.Join(workDir, "leveldb-app-sim")
 	var logger log.Logger
 	if cli.FlagVerboseValue {
@@ -185,7 +189,7 @@ func NewSimulationAppInstance[T SimulationApp](
 	db, err := dbm.NewDB("Simulation", dbm.BackendType(tCfg.DBBackend), dbDir)
 	require.NoError(t, err)
 	t.Cleanup(func() {
-		require.NoError(t, db.Close())
+		_ = db.Close() // ensure db is closed
 	})
 	appOptions := make(simtestutil.AppOptionsMap)
 	appOptions[flags.FlagHome] = workDir