Additional storage engine called "blackhole". Customer request, and for that matter a Zawodny request. With this you can alter table to a type of table that would never store data. Its a /dev/null for a database.

acinclude.m4:
  New macro rule for ha_blackhole.
configure.in:
  Rule enabling blackhole engine
sql/Makefile.am:
  Additions to Makefile for blackhole engine
sql/handler.cc:
  Ifdef enable code for blackhole (and message for "what does this thing do").
sql/handler.h:
  Flag for storage engine type.
sql/mysql_priv.h:
  Added blackhole type.
sql/mysqld.cc:
  Updates for building backhole.
sql/set_var.cc:
  Show variable for blackhole engine

1 files changed, 79 insertions, 0 deletions

diff --git a/sql/ha_blackhole.h b/sql/ha_blackhole.h
new file mode 100644
index 00000000000..538cdd07bde
--- /dev/null
+++ b/sql/ha_blackhole.h
@@ -0,0 +1,79 @@
+/* Copyright (C) 2005 MySQL AB
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#ifdef __GNUC__
+#pragma interface			/* gcc class implementation */
+#endif
+
+/*
+  Class definition for the blackhole storage engine
+  "Dumbest named feature ever"
+*/
+class ha_blackhole: public handler
+{
+  THR_LOCK_DATA lock;      /* MySQL lock */
+  THR_LOCK thr_lock;
+
+public:
+  ha_blackhole(TABLE *table): handler(table)
+  {
+  }
+  ~ha_blackhole()
+  {
+  }
+  /* The name that will be used for display purposes */
+  const char *table_type() const { return "BLACKHOLE"; }
+  /*
+    The name of the index type that will be used for display
+    don't implement this method unless you really have indexes
+   */
+  const char *index_type(uint key_number);
+  const char **bas_ext() const;
+  ulong table_flags() const
+  {
+    return(HA_NULL_IN_KEY | HA_CAN_FULLTEXT | HA_CAN_SQL_HANDLER |
+           HA_DUPP_POS | HA_CAN_INDEX_BLOBS | HA_AUTO_PART_KEY |
+           HA_FILE_BASED | HA_CAN_GEOMETRY | HA_READ_RND_SAME |
+           HA_CAN_INSERT_DELAYED);
+  }
+  ulong index_flags(uint inx, uint part, bool all_parts) const
+  {
+    return ((table->key_info[inx].algorithm == HA_KEY_ALG_FULLTEXT) ?
+            0 : HA_READ_NEXT | HA_READ_PREV | HA_READ_RANGE |
+            HA_READ_ORDER | HA_KEYREAD_ONLY);
+  }
+  /* The following defines can be increased if necessary */
+#define BLACKHOLE_MAX_KEY	64		/* Max allowed keys */
+#define BLACKHOLE_MAX_KEY_SEG	16		/* Max segments for key */
+#define BLACKHOLE_MAX_KEY_LENGTH 1000
+  uint max_supported_keys()          const { return BLACKHOLE_MAX_KEY; }
+  uint max_supported_key_length()    const { return BLACKHOLE_MAX_KEY_LENGTH; }
+  uint max_supported_key_part_length() const { return BLACKHOLE_MAX_KEY_LENGTH; }
+  int open(const char *name, int mode, uint test_if_locked);
+  int close(void);
+  int write_row(byte * buf);
+  int rnd_init(bool scan);
+  int rnd_next(byte *buf);
+  int rnd_pos(byte * buf, byte *pos);
+  void position(const byte *record);
+  void info(uint flag);
+  int external_lock(THD *thd, int lock_type);
+  int create(const char *name, TABLE *table_arg,
+                           HA_CREATE_INFO *create_info);
+  THR_LOCK_DATA **store_lock(THD *thd,
+                                           THR_LOCK_DATA **to,
+                                           enum thr_lock_type lock_type);
+};