diff --git a/hbrdd/dbf/dbf.go b/hbrdd/dbf/dbf.go
index dc834d7..1034188 100644
--- a/hbrdd/dbf/dbf.go
+++ b/hbrdd/dbf/dbf.go
@@ -1115,6 +1115,30 @@ func (a *DBFArea) drainPendingIndexInserts() {
 }
 
 func (a *DBFArea) updateHeader() {
+	// Shared-mode max-merge. A pgserver-style multi-connection
+	// scenario has every peer call Close → updateHeader in arbitrary
+	// order. Each peer's `a.recCount` reflects its own view at the
+	// time of its last Append; if the file has grown since (because
+	// another peer's Append took the append-intent lock and bumped
+	// the disk header), naively writing a.recCount back would
+	// roll the on-disk count BACKWARDS — and subsequent peer SELECTs
+	// would iterate only as far as our stale count, missing rows
+	// that are demonstrably on disk.
+	//
+	// Re-read the disk header and pick the max. This is correct under
+	// the append-intent lock invariant (the bumped count is always
+	// monotonic) and cheap (one stat-sized read). Single-process /
+	// EXCLUSIVE mode still writes its local count unconditionally,
+	// since no peer can have bumped it.
+	if a.shared {
+		if _, err := a.dataFile.Seek(0, 0); err == nil {
+			if hdr, err := ReadHeader(a.dataFile); err == nil {
+				if hdr.RecCount > a.recCount {
+					a.recCount = hdr.RecCount
+				}
+			}
+		}
+	}
 	a.header.RecCount = a.recCount
 	a.header.UpdateDate()