Fix MDEV-12653 Cannot add index for ZIP CONNECT table

  modified:   storage/connect/filamzip.cpp
  modified:   storage/connect/ha_connect.cc
  modified:   storage/connect/tabdos.cpp
  modified:   storage/connect/tabfmt.cpp
  modified:   storage/connect/tabjson.cpp
  modified:   storage/connect/xindex.cpp

storage/connect/filamzip.cpp

@@ -740,7 +740,13 @@ int UNZFAM::Cardinality(PGLOBAL g)
 	int card = -1;
 	int len = GetFileLength(g);
 
-	card = (len / (int)Lrecl) * 2;           // Estimated ???
+	if (len) {
+		// Estimated ???
+		card = (len / (int)Lrecl) * 2;
+		card = card ? card : 10;				// Lrecl can be too big 
+	} else
+		card = 0;
+
 	return card;
 } // end of Cardinality
 

storage/connect/ha_connect.cc

@@ -4601,10 +4601,12 @@ int ha_connect::external_lock(THD *thd, int lock_type)
       DBUG_RETURN(0);
     } else if (g->Xchk) {
       if (!tdbp) {
-        if (!(tdbp= GetTDB(g)))
-          DBUG_RETURN(HA_ERR_INTERNAL_ERROR);
-        else if (!tdbp->GetDef()->Indexable()) {
-          sprintf(g->Message, "external_lock: Table %s is not indexable", tdbp->GetName());
+				if (!(tdbp = GetTDB(g))) {
+//        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);  causes assert error
+					push_warning(thd, Sql_condition::WARN_LEVEL_WARN, 0, g->Message);
+					DBUG_RETURN(0);
+				} else if (!tdbp->GetDef()->Indexable()) {
+					sprintf(g->Message, "external_lock: Table %s is not indexable", tdbp->GetName());
 //        DBUG_RETURN(HA_ERR_INTERNAL_ERROR);  causes assert error
           push_warning(thd, Sql_condition::WARN_LEVEL_WARN, 0, g->Message);
           DBUG_RETURN(0);

storage/connect/tabdos.cpp

@@ -353,7 +353,7 @@ PTDB DOSDEF::GetTable(PGLOBAL g, MODE mode)
 	if (Zipped) {
 #if defined(ZIP_SUPPORT)
 		if (Recfm == RECFM_VAR) {
-			if (mode == MODE_READ || mode == MODE_ANY) {
+			if (mode == MODE_READ || mode == MODE_ANY || mode == MODE_ALTER) {
 				txfp = new(g) UNZFAM(this);
 			} else if (mode == MODE_INSERT) {
 				txfp = new(g) ZIPFAM(this);
@@ -364,7 +364,7 @@ PTDB DOSDEF::GetTable(PGLOBAL g, MODE mode)
 
 			tdbp = new(g) TDBDOS(this, txfp);
 		} else {
-			if (mode == MODE_READ || mode == MODE_ANY) {
+			if (mode == MODE_READ || mode == MODE_ANY || mode == MODE_ALTER) {
 				txfp = new(g) UZXFAM(this);
 			} else if (mode == MODE_INSERT) {
 				txfp = new(g) ZPXFAM(this);

storage/connect/tabfmt.cpp

@@ -517,7 +517,7 @@ PTDB CSVDEF::GetTable(PGLOBAL g, MODE mode)
     /*******************************************************************/
 		if (Zipped) {
 #if defined(ZIP_SUPPORT)
-			if (mode == MODE_READ || mode == MODE_ANY) {
+			if (mode == MODE_READ || mode == MODE_ANY || mode == MODE_ALTER) {
 				txfp = new(g) UNZFAM(this);
 			} else if (mode == MODE_INSERT) {
 				txfp = new(g) ZIPFAM(this);

storage/connect/tabjson.cpp

@@ -443,7 +443,7 @@ PTDB JSONDEF::GetTable(PGLOBAL g, MODE m)
 
 		if (Zipped) {
 #if defined(ZIP_SUPPORT)
-			if (m == MODE_READ || m == MODE_UPDATE) {
+			if (m == MODE_READ || m == MODE_ANY || m == MODE_ALTER) {
 				txfp = new(g) UNZFAM(this);
 			} else if (m == MODE_INSERT) {
 				txfp = new(g) ZIPFAM(this);

storage/connect/xindex.cpp

@@ -969,8 +969,8 @@ bool XINDEX::Init(PGLOBAL g)
     // For DBF tables, Cardinality includes bad or soft deleted lines
     // that are not included in the index, and can be larger then the
     // index size.
-    estim = (Tdbp->Ftype == RECFM_DBF);
-    n = Tdbp->Cardinality(g);      // n is exact table size
+		estim = (Tdbp->Ftype == RECFM_DBF || Tdbp->Txfp->GetAmType() == TYPE_AM_ZIP);
+		n = Tdbp->Cardinality(g);      // n is exact table size
   } else {
     // Variable table not optimized
     estim = true;                  // n is an estimate of the size