Bug #11753490: 44939: sql dumps containing broad views fail when

executing

The problem is that mysql lacks information about the objects a view
depends on so it can't dump views and tables in the proper order.
Thus it needs to create "stand-in" myisam tables for each view while 
dumping the tables that it later drops and replaces with the actual view
view definition.
But since views can have much more columns than an actual table creating
these stand-in tables may be problematic.

There's no way to portably find out how many columns an mysiam table
can have. It's a complicated formula depending on internal server constants.
Thus we can't have a reliable error check without repeating the logic and 
the formula inside mysqldump.

1. Changed the type of the columns of the stand-in tables mysqldump
makes to satisfy view dependencies from the original type to smallint 
to save on row space.

2. Added a warning on the mysqldump's standard error for a possible 
problems replaying the dump file if the columns of a view exceed 1000.

3. Added a test case.

1 files changed, 28 insertions, 7 deletions

diff --git a/client/mysqldump.c b/client/mysqldump.c
index e273ca0e7fd..dcfe25a5f61 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -2558,6 +2558,7 @@ static uint get_table_structure(char *table, char *db, char *table_type,
       if (strcmp(field->name, "View") == 0)
       {
         char *scv_buff= NULL;
+        my_ulonglong n_cols;
 
         verbose_msg("-- It's a view, create dummy table for view\n");
 
@@ -2572,8 +2573,8 @@ static uint get_table_structure(char *table, char *db, char *table_type,
           the same name in order to satisfy views that depend on this view.
           The table will be removed when the actual view is created.
 
-          The properties of each column, aside from the data type, are not
-          preserved in this temporary table, because they are not necessary.
+          The properties of each column, are not preserved in this temporary
+          table, because they are not necessary.
 
           This will not be necessary once we can determine dependencies
           between views and can simply dump them in the appropriate order.
@@ -2600,8 +2601,23 @@ static uint get_table_structure(char *table, char *db, char *table_type,
         else
           my_free(scv_buff);
 
-        if (mysql_num_rows(result))
+        n_cols= mysql_num_rows(result);
+        if (0 != n_cols)
         {
+
+          /*
+            The actual formula is based on the column names and how the .FRM
+            files are stored and is too volatile to be repeated here.
+            Thus we simply warn the user if the columns exceed a limit we
+            know works most of the time.
+          */
+          if (n_cols >= 1000)
+            fprintf(stderr,
+                    "-- Warning: Creating a stand-in table for view %s may"
+                    " fail when replaying the dump file produced because "
+                    "of the number of columns exceeding 1000. Exercise "
+                    "caution when replaying the produced dump file.\n", 
+                    table);
           if (opt_drop)
           {
             /*
@@ -2628,14 +2644,19 @@ static uint get_table_structure(char *table, char *db, char *table_type,
 
           row= mysql_fetch_row(result);
 
-          fprintf(sql_file, "  %s %s", quote_name(row[0], name_buff, 0),
-                  row[1]);
+          /*
+            The actual column type doesn't matter anyway, since the table will
+            be dropped at run time.
+            We do tinyint to avoid hitting the row size limit.
+          */
+          fprintf(sql_file, "  %s tinyint NOT NULL",
+                  quote_name(row[0], name_buff, 0));
 
           while((row= mysql_fetch_row(result)))
           {
             /* col name, col type */
-            fprintf(sql_file, ",\n  %s %s",
-                    quote_name(row[0], name_buff, 0), row[1]);
+            fprintf(sql_file, ",\n  %s tinyint NOT NULL",
+                    quote_name(row[0], name_buff, 0));
           }
 
           /*