BUG#13406 - incorrect amount of "records deleted" in CSV.

Fallback to row-wise delete if number or rows in the table is unknown

mysql-test/r/csv.result

@@ -4976,3 +4976,27 @@ c1
 4
 5
 DROP TABLE bug14672;
+create table t1 (a int) engine=csv;
+insert t1 values (1);
+delete from t1;
+affected rows: 1
+delete from t1;
+affected rows: 0
+insert t1 values (1),(2);
+delete from t1;
+affected rows: 2
+insert t1 values (1),(2),(3);
+flush tables;
+delete from t1;
+affected rows: 3
+insert t1 values (1),(2),(3),(4);
+flush tables;
+select count(*) from t1;
+count(*)
+4
+delete from t1;
+affected rows: 4
+insert t1 values (1),(2),(3),(4),(5);
+truncate table t1;
+affected rows: 0
+drop table t1;

mysql-test/t/csv.test

@@ -1352,3 +1352,35 @@ SELECT * FROM bug14672;
 DROP TABLE bug14672;
 
 # End of 4.1 tests
+
+#
+# BUG#13406 - incorrect amount of "records deleted"
+#
+
+create table t1 (a int) engine=csv;
+insert t1 values (1);
+--enable_info
+delete from t1;                 -- delete_row
+delete from t1;                 -- delete_all_rows
+--disable_info
+insert t1 values (1),(2);
+--enable_info
+delete from t1;                 -- delete_all_rows
+--disable_info
+insert t1 values (1),(2),(3);
+flush tables;
+--enable_info
+delete from t1;                 -- delete_row
+--disable_info
+insert t1 values (1),(2),(3),(4);
+flush tables;
+select count(*) from t1;
+--enable_info
+delete from t1;                 -- delete_all_rows
+--disable_info
+insert t1 values (1),(2),(3),(4),(5);
+--enable_info
+truncate table t1;              -- truncate
+--disable_info
+drop table t1;
+

sql/examples/ha_tina.cc

@@ -274,7 +274,8 @@ ha_tina::ha_tina(TABLE *table_arg)
     These definitions are found in hanler.h
     These are not probably completely right.
   */
-  current_position(0), next_position(0), chain_alloced(0), chain_size(DEFAULT_CHAIN_LENGTH)
+  current_position(0), next_position(0), chain_alloced(0),
+  chain_size(DEFAULT_CHAIN_LENGTH), records_is_known(0)
 {
   /* Set our original buffers from pre-allocated memory */
   buffer.set(byte_buffer, IO_SIZE, system_charset_info);
@@ -504,6 +505,7 @@ int ha_tina::write_row(byte * buf)
   */
   if (get_mmap(share, 0) > 0) 
     DBUG_RETURN(-1);
+  records++;
   DBUG_RETURN(0);
 }
 
@@ -668,6 +670,7 @@ int ha_tina::rnd_init(bool scan)
 
   current_position= next_position= 0;
   records= 0;
+  records_is_known= 0;
   chain_ptr= chain;
 #ifdef HAVE_MADVISE
   if (scan)
@@ -745,7 +748,7 @@ void ha_tina::info(uint flag)
 {
   DBUG_ENTER("ha_tina::info");
   /* This is a lie, but you don't want the optimizer to see zero or 1 */
-  if (records < 2) 
+  if (!records_is_known && records < 2) 
     records= 2;
   DBUG_VOID_RETURN;
 }
@@ -780,6 +783,8 @@ int ha_tina::rnd_end()
 {
   DBUG_ENTER("ha_tina::rnd_end");
 
+  records_is_known= 1;
+
   /* First position will be truncate position, second will be increment */
   if ((chain_ptr - chain)  > 0)
   {
@@ -824,17 +829,21 @@ int ha_tina::rnd_end()
 }
 
 /* 
-  Truncate table and others of its ilk call this. 
+  DELETE without WHERE calls it
 */
 int ha_tina::delete_all_rows()
 {
   DBUG_ENTER("ha_tina::delete_all_rows");
 
+  if (!records_is_known)
+    return (my_errno=HA_ERR_WRONG_COMMAND);
+
   int rc= my_chsize(share->data_file, 0, 0, MYF(MY_WME));
 
   if (get_mmap(share, 0) > 0) 
     DBUG_RETURN(-1);
 
+  records=0;
   DBUG_RETURN(rc);
 }
 

sql/examples/ha_tina.h

@@ -48,6 +48,7 @@ class ha_tina: public handler
   tina_set *chain_ptr;
   byte chain_alloced;
   uint32 chain_size;
+  bool records_is_known;
 
 public:
   ha_tina(TABLE *table_arg);