diff --git a/cmd/syncv3/main.go b/cmd/syncv3/main.go
index 274bd084..9938ecc3 100644
--- a/cmd/syncv3/main.go
+++ b/cmd/syncv3/main.go
@@ -2,6 +2,14 @@ package main
 
 import (
 	"fmt"
+	"net/http"
+	_ "net/http/pprof"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+	"time"
+
 	"github.com/getsentry/sentry-go"
 	sentryhttp "github.com/getsentry/sentry-go/http"
 	syncv3 "github.com/matrix-org/sliding-sync"
@@ -10,13 +18,6 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/rs/zerolog"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
-	"net/http"
-	_ "net/http/pprof"
-	"os"
-	"os/signal"
-	"strings"
-	"syscall"
-	"time"
 )
 
 var GitCommit string
@@ -163,6 +164,8 @@ func main() {
 
 	h2, h3 := syncv3.Setup(args[EnvServer], args[EnvDB], args[EnvSecret], syncv3.Opts{
 		AddPrometheusMetrics: args[EnvPrometheus] != "",
+		DBMaxConns:           100,
+		DBConnMaxIdleTime:    time.Hour,
 	})
 
 	go h2.StartV2Pollers()
diff --git a/state/storage.go b/state/storage.go
index a6af1c71..ff70d981 100644
--- a/state/storage.go
+++ b/state/storage.go
@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"os"
 	"strings"
-	"time"
 
 	"github.com/getsentry/sentry-go"
 
@@ -58,9 +57,6 @@ func NewStorage(postgresURI string) *Storage {
 		// TODO: if we panic(), will sentry have a chance to flush the event?
 		logger.Panic().Err(err).Str("uri", postgresURI).Msg("failed to open SQL DB")
 	}
-	db.SetMaxOpenConns(100)
-	db.SetMaxIdleConns(80)
-	db.SetConnMaxLifetime(time.Hour)
 	acc := &Accumulator{
 		db:            db,
 		roomsTable:    NewRoomsTable(db),
diff --git a/sync2/storage.go b/sync2/storage.go
index 88d3c759..5f484179 100644
--- a/sync2/storage.go
+++ b/sync2/storage.go
@@ -2,7 +2,6 @@ package sync2
 
 import (
 	"os"
-	"time"
 
 	"github.com/getsentry/sentry-go"
 	"github.com/jmoiron/sqlx"
@@ -27,9 +26,6 @@ func NewStore(postgresURI, secret string) *Storage {
 		// TODO: if we panic(), will sentry have a chance to flush the event?
 		logger.Panic().Err(err).Str("uri", postgresURI).Msg("failed to open SQL DB")
 	}
-	db.SetMaxOpenConns(100)
-	db.SetMaxIdleConns(80)
-	db.SetConnMaxLifetime(time.Hour)
 	return &Storage{
 		DevicesTable: NewDevicesTable(db),
 		TokensTable:  NewTokensTable(db, secret),
diff --git a/sync3/handler/handler.go b/sync3/handler/handler.go
index 98d4e610..31870c5d 100644
--- a/sync3/handler/handler.go
+++ b/sync3/handler/handler.go
@@ -65,7 +65,7 @@ type SyncLiveHandler struct {
 }
 
 func NewSync3Handler(
-	store *state.Storage, storev2 *sync2.Storage, v2Client sync2.Client, postgresDBURI, secret string,
+	store *state.Storage, storev2 *sync2.Storage, v2Client sync2.Client, secret string,
 	pub pubsub.Notifier, sub pubsub.Listener, enablePrometheus bool, maxPendingEventUpdates int,
 ) (*SyncLiveHandler, error) {
 	logger.Info().Msg("creating handler")
diff --git a/tests-integration/db_test.go b/tests-integration/db_test.go
new file mode 100644
index 00000000..3897009e
--- /dev/null
+++ b/tests-integration/db_test.go
@@ -0,0 +1,103 @@
+package syncv3
+
+import (
+	"encoding/json"
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	syncv3 "github.com/matrix-org/sliding-sync"
+	"github.com/matrix-org/sliding-sync/sync2"
+	"github.com/matrix-org/sliding-sync/sync3"
+	"github.com/matrix-org/sliding-sync/testutils"
+	"github.com/matrix-org/sliding-sync/testutils/m"
+)
+
+// Test that the proxy works fine with low max conns. Low max conns can be a problem
+// if a request A needs 2 conns to respond and that blocks forward progress on the server,
+// and the request can only obtain 1 conn.
+func TestMaxDBConns(t *testing.T) {
+	pqString := testutils.PrepareDBConnectionString()
+	// setup code
+	v2 := runTestV2Server(t)
+	opts := syncv3.Opts{
+		DBMaxConns: 1,
+	}
+	v3 := runTestServer(t, v2, pqString, opts)
+	defer v2.close()
+	defer v3.close()
+
+	testMaxDBConns := func() {
+		// make N users and drip feed some events, make sure they are all seen
+		numUsers := 5
+		var wg sync.WaitGroup
+		wg.Add(numUsers)
+		for i := 0; i < numUsers; i++ {
+			go func(n int) {
+				defer wg.Done()
+				userID := fmt.Sprintf("@maxconns_%d:localhost", n)
+				token := fmt.Sprintf("maxconns_%d", n)
+				roomID := fmt.Sprintf("!maxconns_%d", n)
+				v2.addAccount(t, userID, token)
+				v2.queueResponse(userID, sync2.SyncResponse{
+					Rooms: sync2.SyncRoomsResponse{
+						Join: v2JoinTimeline(roomEvents{
+							roomID: roomID,
+							state:  createRoomState(t, userID, time.Now()),
+						}),
+					},
+				})
+				// initial sync
+				res := v3.mustDoV3Request(t, token, sync3.Request{
+					Lists: map[string]sync3.RequestList{"a": {
+						Ranges: sync3.SliceRanges{
+							[2]int64{0, 1},
+						},
+						RoomSubscription: sync3.RoomSubscription{
+							TimelineLimit: 1,
+						},
+					}},
+				})
+				t.Logf("user %s has done an initial /sync OK", userID)
+				m.MatchResponse(t, res, m.MatchList("a", m.MatchV3Count(1), m.MatchV3Ops(
+					m.MatchV3SyncOp(0, 0, []string{roomID}),
+				)), m.MatchRoomSubscriptionsStrict(map[string][]m.RoomMatcher{
+					roomID: {
+						m.MatchJoinCount(1),
+					},
+				}))
+				// drip feed and get update
+				dripMsg := testutils.NewEvent(t, "m.room.message", userID, map[string]interface{}{
+					"msgtype": "m.text",
+					"body":    "drip drip",
+				})
+				v2.queueResponse(userID, sync2.SyncResponse{
+					Rooms: sync2.SyncRoomsResponse{
+						Join: v2JoinTimeline(roomEvents{
+							roomID: roomID,
+							events: []json.RawMessage{
+								dripMsg,
+							},
+						}),
+					},
+				})
+				t.Logf("user %s has queued the drip", userID)
+				v2.waitUntilEmpty(t, userID)
+				t.Logf("user %s poller has received the drip", userID)
+				res = v3.mustDoV3RequestWithPos(t, token, res.Pos, sync3.Request{})
+				m.MatchResponse(t, res, m.MatchRoomSubscriptionsStrict(map[string][]m.RoomMatcher{
+					roomID: {
+						m.MatchRoomTimelineMostRecent(1, []json.RawMessage{dripMsg}),
+					},
+				}))
+				t.Logf("user %s has received the drip", userID)
+			}(i)
+		}
+		wg.Wait()
+	}
+
+	testMaxDBConns()
+	v3.restart(t, v2, pqString, opts)
+	testMaxDBConns()
+}
diff --git a/tests-integration/v3_test.go b/tests-integration/v3_test.go
index cd8bd2c1..de72d954 100644
--- a/tests-integration/v3_test.go
+++ b/tests-integration/v3_test.go
@@ -291,11 +291,11 @@ func (s *testV3Server) close() {
 	s.h2.Teardown()
 }
 
-func (s *testV3Server) restart(t *testing.T, v2 *testV2Server, pq string) {
+func (s *testV3Server) restart(t *testing.T, v2 *testV2Server, pq string, opts ...syncv3.Opts) {
 	t.Helper()
 	log.Printf("restarting server")
 	s.close()
-	ss := runTestServer(t, v2, pq)
+	ss := runTestServer(t, v2, pq, opts...)
 	// replace all the fields which will be close()d to ensure we don't leak
 	s.srv = ss.srv
 	s.h2 = ss.h2
@@ -366,20 +366,22 @@ func runTestServer(t testutils.TestBenchInterface, v2Server *testV2Server, postg
 	//tests often repeat requests. To ensure tests remain fast, reduce the spam protection limits.
 	sync3.SpamProtectionInterval = time.Millisecond
 
-	metricsEnabled := false
-	maxPendingEventUpdates := 200
+	combinedOpts := syncv3.Opts{
+		TestingSynchronousPubsub: true, // critical to avoid flakey tests
+		AddPrometheusMetrics:     false,
+		MaxPendingEventUpdates:   200,
+	}
 	if len(opts) > 0 {
-		metricsEnabled = opts[0].AddPrometheusMetrics
-		if opts[0].MaxPendingEventUpdates > 0 {
-			maxPendingEventUpdates = opts[0].MaxPendingEventUpdates
+		opt := opts[0]
+		combinedOpts.AddPrometheusMetrics = opt.AddPrometheusMetrics
+		combinedOpts.DBConnMaxIdleTime = opt.DBConnMaxIdleTime
+		combinedOpts.DBMaxConns = opt.DBMaxConns
+		if opt.MaxPendingEventUpdates > 0 {
+			combinedOpts.MaxPendingEventUpdates = opt.MaxPendingEventUpdates
 			handler.BufferWaitTime = 5 * time.Millisecond
 		}
 	}
-	h2, h3 := syncv3.Setup(v2Server.url(), postgresConnectionString, os.Getenv("SYNCV3_SECRET"), syncv3.Opts{
-		TestingSynchronousPubsub: true, // critical to avoid flakey tests
-		MaxPendingEventUpdates:   maxPendingEventUpdates,
-		AddPrometheusMetrics:     metricsEnabled,
-	})
+	h2, h3 := syncv3.Setup(v2Server.url(), postgresConnectionString, os.Getenv("SYNCV3_SECRET"), combinedOpts)
 	// for ease of use we don't start v2 pollers at startup in tests
 	r := mux.NewRouter()
 	r.Use(hlog.NewHandler(logger))
diff --git a/v3.go b/v3.go
index acb87575..74ae2be2 100644
--- a/v3.go
+++ b/v3.go
@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/getsentry/sentry-go"
+	"github.com/jmoiron/sqlx"
 
 	"github.com/gorilla/mux"
 	"github.com/matrix-org/sliding-sync/internal"
@@ -36,6 +37,9 @@ type Opts struct {
 	// if true, publishing messages will block until the consumer has consumed it.
 	// Assumes a single producer and a single consumer.
 	TestingSynchronousPubsub bool
+
+	DBMaxConns        int
+	DBConnMaxIdleTime time.Duration
 }
 
 type server struct {
@@ -75,6 +79,18 @@ func Setup(destHomeserver, postgresURI, secret string, opts Opts) (*handler2.Han
 	}
 	store := state.NewStorage(postgresURI)
 	storev2 := sync2.NewStore(postgresURI, secret)
+	for _, db := range []*sqlx.DB{store.DB, storev2.DB} {
+		if opts.DBMaxConns > 0 {
+			// https://github.com/go-sql-driver/mysql#important-settings
+			// "db.SetMaxIdleConns() is recommended to be set same to db.SetMaxOpenConns(). When it is smaller
+			// than SetMaxOpenConns(), connections can be opened and closed much more frequently than you expect."
+			db.SetMaxOpenConns(opts.DBMaxConns)
+			db.SetMaxIdleConns(opts.DBMaxConns)
+		}
+		if opts.DBConnMaxIdleTime > 0 {
+			db.SetConnMaxIdleTime(opts.DBConnMaxIdleTime)
+		}
+	}
 	bufferSize := 50
 	if opts.TestingSynchronousPubsub {
 		bufferSize = 0
@@ -93,7 +109,7 @@ func Setup(destHomeserver, postgresURI, secret string, opts Opts) (*handler2.Han
 	pMap.SetCallbacks(h2)
 
 	// create v3 handler
-	h3, err := handler.NewSync3Handler(store, storev2, v2Client, postgresURI, secret, pubSub, pubSub, opts.AddPrometheusMetrics, opts.MaxPendingEventUpdates)
+	h3, err := handler.NewSync3Handler(store, storev2, v2Client, secret, pubSub, pubSub, opts.AddPrometheusMetrics, opts.MaxPendingEventUpdates)
 	if err != nil {
 		panic(err)
 	}