1 files changed, 40 insertions, 0 deletions
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 26f253a6f8e..491a4c8ca1b 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -259,6 +259,21 @@ protected:
 #define USER_VARS_HASH_SIZE     16
 #define TABLE_OPEN_CACHE_MIN    64
 #define TABLE_OPEN_CACHE_DEFAULT 64
+#define TABLE_DEF_CACHE_DEFAULT 256
+/**
+  We must have room for at least 256 table definitions in the table
+  cache, since otherwise there is no chance prepared
+  statements that use these many tables can work.
+  Prepared statements use table definition cache ids (table_map_id)
+  as table version identifiers. If the table definition
+  cache size is less than the number of tables used in a statement,
+  the contents of the table definition cache is guaranteed to rotate
+  between a prepare and execute. This leads to stable validation
+  errors. In future we shall use more stable version identifiers,
+  for now the only solution is to ensure that the table definition
+  cache can contain at least all tables of a given statement.
+*/
+#define TABLE_DEF_CACHE_MIN     256
 
 /* 
  Value of 9236 discovered through binary search 2006-09-26 on Ubuntu Dapper
@@ -670,6 +685,31 @@ const char *set_thd_proc_info(THD *thd, const char *info,
                               const char *calling_file, 
                               const unsigned int calling_line);
 
+/**
+  Enumerate possible types of a table from re-execution
+  standpoint.
+  TABLE_LIST class has a member of this type.
+  At prepared statement prepare, this member is assigned a value
+  as of the current state of the database. Before (re-)execution
+  of a prepared statement, we check that the value recorded at
+  prepare matches the type of the object we obtained from the
+  table definition cache.
+
+  @sa check_and_update_metadata_version()
+  @sa Execute_observer
+  @sa Prepared_statement::reprepare()
+*/
+
+enum enum_metadata_type
+{
+  /** Initial value set by the parser */
+  METADATA_NULL= 0,
+  METADATA_VIEW,
+  METADATA_BASE_TABLE,
+  METADATA_I_S_TABLE,
+  METADATA_TMP_TABLE
+};
+
 /*
   External variables
 */