diff --git a/_FiveSql2/src/TSqlExecutor.prg b/_FiveSql2/src/TSqlExecutor.prg
index a164be6..0431f7d 100644
--- a/_FiveSql2/src/TSqlExecutor.prg
+++ b/_FiveSql2/src/TSqlExecutor.prg
@@ -202,7 +202,18 @@ METHOD OpenTable( cTable, cAlias ) CLASS TSqlExecutor
 
    nWA := ::oIndex:OpenTable( cTable, cAlias, .T., .T. )
    IF nWA > 0
-      AAdd( ::aOpened, cAlias )
+      /* When the WA cache is on, hand lifetime to the cache so CloseOpened
+       * leaves the mmap alive for the next query. Profile showed
+       * rtlDbCloseArea + munmap at ~30% of SELECT CPU prior to this branch.
+       *
+       * Skip caching when the alias is an AcquireTemp-generated "FA_####"
+       * token: those change every query (self-joins, nested depth), so
+       * caching them just leaks entries while delivering zero reuse. */
+      IF SqlWACacheIsEnabled() .AND. ! ( Left( cAlias, 3 ) == "FA_" )
+         SqlWACachePut( cAlias, nWA )
+      ELSE
+         AAdd( ::aOpened, cAlias )
+      ENDIF
       /* Register with alias manager if not already tracked */
       lFound := .F.
       FOR i := 1 TO Len( ::oAlias:aSlots )