add details to roTxsLimiter errors

Author: battlmonstr

erigon-lib/kv/mdbx/kv_mdbx.go

@@ -750,7 +750,7 @@ func (db *MdbxKV) BeginRo(ctx context.Context) (txn kv.Tx, err error) {
 	// will return nil err if context is cancelled (may appear to acquire the semaphore)
 	if semErr := db.roTxsLimiter.Acquire(ctx, 1); semErr != nil {
 		db.trackTxEnd()
-		return nil, semErr
+		return nil, fmt.Errorf("mdbx.MdbxKV.BeginRo: roTxsLimiter error %w", semErr)
 	}
 
 	defer func() {

erigon-lib/kv/remotedb/kv_remote.go

@@ -24,13 +24,14 @@ import (
 	"runtime"
 	"unsafe"
 
-	"github.com/ledgerwatch/erigon-lib/kv/iter"
-	"github.com/ledgerwatch/erigon-lib/kv/order"
 	"github.com/ledgerwatch/log/v3"
 	"golang.org/x/sync/semaphore"
 	"google.golang.org/grpc"
 	"google.golang.org/protobuf/types/known/emptypb"
 
+	"github.com/ledgerwatch/erigon-lib/kv/iter"
+	"github.com/ledgerwatch/erigon-lib/kv/order"
+
 	"github.com/ledgerwatch/erigon-lib/gointerfaces"
 	"github.com/ledgerwatch/erigon-lib/gointerfaces/grpcutil"
 	"github.com/ledgerwatch/erigon-lib/gointerfaces/remote"
@@ -160,7 +161,7 @@ func (db *DB) BeginRo(ctx context.Context) (txn kv.Tx, err error) {
 	}
 
 	if semErr := db.roTxsLimiter.Acquire(ctx, 1); semErr != nil {
-		return nil, semErr
+		return nil, fmt.Errorf("remotedb.DB.BeginRo: roTxsLimiter error %w", semErr)
 	}
 
 	defer func() {