Finalize storage engine plugins

Give BerkeleyDB savepoints
Remove "enum db_type" from most of the code


storage/example/ha_example.h:
  Rename: sql/examples/ha_example.h -> storage/example/ha_example.h
storage/csv/ha_tina.h:
  Rename: sql/examples/ha_tina.h -> storage/csv/ha_tina.h
config/ac-macros/storage.m4:
  if hton name is "no", then we don't install it as a builtin
configure.in:
  pluggable changes
include/plugin.h:
  version field
mysql-test/r/bdb.result:
  savepoint results copied from innodb test
mysql-test/r/information_schema.result:
  PLUGINS information schema
mysql-test/r/information_schema_db.result:
  PLUGINS information schema
mysql-test/t/bdb.test:
  savepoint test copied from innodb test
sql/Makefile.am:
  tina and example are not here anymore
sql/authors.h:
  minor tweek
sql/ha_archive.cc:
  remove unwanted handlerton entries
sql/ha_berkeley.cc:
  remove unwanted handlerton entries
  support for savepoints
  changes to show logs
sql/ha_blackhole.cc:
  remove unwanted handlerton entries
sql/ha_federated.cc:
  remove unwanted handlerton entries
sql/ha_heap.cc:
  remove unwanted handlerton entries
sql/ha_innodb.cc:
  remove unwanted handlerton entries
  changes for show status
sql/ha_myisam.cc:
  remove unwanted handlerton entries
sql/ha_myisammrg.cc:
  remove unwanted handlerton entries
sql/ha_ndbcluster.cc:
  remove unwanted handlerton entries
  changes to stat_print
sql/ha_partition.cc:
  remove unwanted handlerton entries
  bye bye enum db_type
sql/ha_partition.h:
  bye bye enum db_type
sql/handler.cc:
  remove unwanted handlerton entries
  bye bye enum db_type
sql/handler.h:
  remove unwanted handlerton entries
  bye bye enum db_type
  changes to stat_print_fn
sql/item_sum.cc:
  bye bye enum db_type
sql/log.cc:
  remove unwanted handlerton entries
sql/mysql_priv.h:
  bye bye enum db_type
sql/mysqld.cc:
  bye bye enum db_type
  reorder plugin initialization
sql/set_var.cc:
  bye bye enum db_type
sql/set_var.h:
  bye bye enum db_type
sql/sql_base.cc:
  bye bye enum db_type
sql/sql_cache.cc:
  bye bye enum db_type
sql/sql_class.h:
  bye bye enum db_type
sql/sql_delete.cc:
  bye bye enum db_type
sql/sql_insert.cc:
  bye bye enum db_type
sql/sql_lex.h:
  show plugin
sql/sql_parse.cc:
  bye bye enum db_type
sql/sql_partition.cc:
  bye bye enum db_type
sql/sql_plugin.cc:
  loadable storage engines
sql/sql_plugin.h:
  loadable storage engines
sql/sql_rename.cc:
  bye bye enum db_type
sql/sql_select.cc:
  bye bye enum db_type
sql/sql_show.cc:
  SHOW PLUGIN
  PLUGINS information schema
  changes to show engines
sql/sql_table.cc:
  bye bye enum db_type
sql/sql_view.cc:
  bye bye enum db_type
sql/sql_view.h:
  bye bye enum db_type
sql/sql_yacc.yy:
  bye bye enum db_type
sql/table.cc:
  bye bye enum db_type
sql/table.h:
  bye bye enum db_type
sql/unireg.cc:
  bye bye enum db_type
storage/csv/ha_tina.cc:
  make tina into a loadable plugin
storage/example/ha_example.cc:
  make into a plugin
storage/csv/Makefile.am:
  New BitKeeper file ``storage/csv/Makefile.am''
storage/example/Makefile.am:
  New BitKeeper file ``storage/example/Makefile.am''

3 files changed, 934 insertions, 0 deletions

diff --git a/storage/example/Makefile.am b/storage/example/Makefile.am
new file mode 100644
index 00000000000..d5896946c5b
--- /dev/null
+++ b/storage/example/Makefile.am
@@ -0,0 +1,39 @@
+# Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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
+
+#called from the top level Makefile
+
+MYSQLDATAdir =          $(localstatedir)
+MYSQLSHAREdir =         $(pkgdatadir)
+MYSQLBASEdir=           $(prefix)
+MYSQLLIBdir=            $(pkglibdir)
+INCLUDES =              -I$(top_srcdir)/include \
+			-I$(top_srcdir)/regex \
+			-I$(top_srcdir)/sql \
+                        -I$(srcdir)
+WRAPLIBS=
+
+pkglib_LTLIBRARIES =	ha_example.la
+
+ha_example_la_LDFLAGS =	-module
+ha_example_la_SOURCES =	ha_example.cc
+
+LDADD =
+
+DEFS =                  -DMYSQL_SERVER @DEFS@
+
+# Don't update the files from bitkeeper
+%::SCCS/s.%
diff --git a/storage/example/ha_example.cc b/storage/example/ha_example.cc
new file mode 100644
index 00000000000..74f25d1411d
--- /dev/null
+++ b/storage/example/ha_example.cc
@@ -0,0 +1,740 @@
+/* Copyright (C) 2003 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 */
+
+/*
+  ha_example is a stubbed storage engine. It does nothing at this point. It
+  will let you create/open/delete tables but that is all. You can enable it
+  in your buld by doing the following during your build process:
+  ./configure --with-example-storage-engine
+
+  Once this is done mysql will let you create tables with:
+  CREATE TABLE A (...) ENGINE=EXAMPLE;
+
+  The example is setup to use table locks. It implements an example "SHARE"
+  that is inserted into a hash by table name. You can use this to store
+  information of state that any example handler object will be able to see
+  if it is using the same table.
+
+  Please read the object definition in ha_example.h before reading the rest
+  if this file.
+
+  To get an idea of what occurs here is an example select that would do a
+  scan of an entire table:
+  ha_example::store_lock
+  ha_example::external_lock
+  ha_example::info
+  ha_example::rnd_init
+  ha_example::extra
+  ENUM HA_EXTRA_CACHE   Cash record in HA_rrnd()
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::rnd_next
+  ha_example::extra
+  ENUM HA_EXTRA_NO_CACHE   End cacheing of records (def)
+  ha_example::external_lock
+  ha_example::extra
+  ENUM HA_EXTRA_RESET   Reset database to after open
+
+  In the above example has 9 row called before rnd_next signalled that it was
+  at the end of its data. In the above example the table was already opened
+  (or you would have seen a call to ha_example::open(). Calls to
+  ha_example::extra() are hints as to what will be occuring to the request.
+
+  Happy coding!
+    -Brian
+*/
+
+#ifdef USE_PRAGMA_IMPLEMENTATION
+#pragma implementation        // gcc: Class implementation
+#endif
+
+#include "../mysql_priv.h"
+#include <plugin.h>
+
+#include "ha_example.h"
+
+static handler* example_create_handler(TABLE_SHARE *table);
+static int example_init_func();
+
+handlerton example_hton= {
+  MYSQL_HANDLERTON_INTERFACE_VERSION,
+  "EXAMPLE",
+  SHOW_OPTION_YES,
+  "Example storage engine", 
+  DB_TYPE_EXAMPLE_DB,
+  (bool (*)()) example_init_func,
+  0,       /* slot */
+  0,       /* savepoint size. */
+  NULL,    /* close_connection */
+  NULL,    /* savepoint */
+  NULL,    /* rollback to savepoint */
+  NULL,    /* release savepoint */
+  NULL,    /* commit */
+  NULL,    /* rollback */
+  NULL,    /* prepare */
+  NULL,    /* recover */
+  NULL,    /* commit_by_xid */
+  NULL,    /* rollback_by_xid */
+  NULL,    /* create_cursor_read_view */
+  NULL,    /* set_cursor_read_view */
+  NULL,    /* close_cursor_read_view */
+  example_create_handler,    /* Create a new handler */
+  NULL,    /* Drop a database */
+  NULL,    /* Panic call */
+  NULL,    /* Release temporary latches */
+  NULL,    /* Update Statistics */
+  NULL,    /* Start Consistent Snapshot */
+  NULL,    /* Flush logs */
+  NULL,    /* Show status */
+  NULL,    /* Replication Report Sent Binlog */
+  HTON_CAN_RECREATE
+};
+
+/* Variables for example share methods */
+static HASH example_open_tables; // Hash used to track open tables
+pthread_mutex_t example_mutex;   // This is the mutex we use to init the hash
+static int example_init= 0;      // Variable for checking the init state of hash
+
+
+/*
+  Function we use in the creation of our hash to get key.
+*/
+static byte* example_get_key(EXAMPLE_SHARE *share,uint *length,
+                             my_bool not_used __attribute__((unused)))
+{
+  *length=share->table_name_length;
+  return (byte*) share->table_name;
+}
+
+
+static int example_init_func()
+{
+  if (!example_init)
+  {
+    example_init++;
+    VOID(pthread_mutex_init(&example_mutex,MY_MUTEX_INIT_FAST));
+    (void) hash_init(&example_open_tables,system_charset_info,32,0,0,
+                     (hash_get_key) example_get_key,0,0);
+  }
+  return 0;
+}
+
+static int example_done_func()
+{
+  if (example_init)
+  {
+    if (example_open_tables.records)
+    {
+      return 1;
+    }
+    hash_free(&example_open_tables);
+    pthread_mutex_destroy(&example_mutex);
+    example_init--;
+  }
+  return 0;
+}
+
+
+/*
+  Example of simple lock controls. The "share" it creates is structure we will
+  pass to each example handler. Do you have to have one of these? Well, you have
+  pieces that are used for locking, and they are needed to function.
+*/
+static EXAMPLE_SHARE *get_share(const char *table_name, TABLE *table)
+{
+  EXAMPLE_SHARE *share;
+  uint length;
+  char *tmp_name;
+
+  pthread_mutex_lock(&example_mutex);
+  length=(uint) strlen(table_name);
+
+  if (!(share=(EXAMPLE_SHARE*) hash_search(&example_open_tables,
+                                           (byte*) table_name,
+                                           length)))
+  {
+    if (!(share=(EXAMPLE_SHARE *)
+          my_multi_malloc(MYF(MY_WME | MY_ZEROFILL),
+                          &share, sizeof(*share),
+                          &tmp_name, length+1,
+                          NullS)))
+    {
+      pthread_mutex_unlock(&example_mutex);
+      return NULL;
+    }
+
+    share->use_count=0;
+    share->table_name_length=length;
+    share->table_name=tmp_name;
+    strmov(share->table_name,table_name);
+    if (my_hash_insert(&example_open_tables, (byte*) share))
+      goto error;
+    thr_lock_init(&share->lock);
+    pthread_mutex_init(&share->mutex,MY_MUTEX_INIT_FAST);
+  }
+  share->use_count++;
+  pthread_mutex_unlock(&example_mutex);
+
+  return share;
+
+error:
+  pthread_mutex_destroy(&share->mutex);
+  my_free((gptr) share, MYF(0));
+
+  return NULL;
+}
+
+
+/*
+  Free lock controls. We call this whenever we close a table. If the table had
+  the last reference to the share then we free memory associated with it.
+*/
+static int free_share(EXAMPLE_SHARE *share)
+{
+  pthread_mutex_lock(&example_mutex);
+  if (!--share->use_count)
+  {
+    hash_delete(&example_open_tables, (byte*) share);
+    thr_lock_delete(&share->lock);
+    pthread_mutex_destroy(&share->mutex);
+    my_free((gptr) share, MYF(0));
+  }
+  pthread_mutex_unlock(&example_mutex);
+
+  return 0;
+}
+
+
+static handler* example_create_handler(TABLE_SHARE *table)
+{
+  return new ha_example(table);
+}
+
+
+ha_example::ha_example(TABLE_SHARE *table_arg)
+  :handler(&example_hton, table_arg)
+{}
+
+/*
+  If frm_error() is called then we will use this to to find out what file extentions
+  exist for the storage engine. This is also used by the default rename_table and
+  delete_table method in handler.cc.
+*/
+static const char *ha_example_exts[] = {
+  NullS
+};
+
+const char **ha_example::bas_ext() const
+{
+  return ha_example_exts;
+}
+
+
+/*
+  Used for opening tables. The name will be the name of the file.
+  A table is opened when it needs to be opened. For instance
+  when a request comes in for a select on the table (tables are not
+  open and closed for each request, they are cached).
+
+  Called from handler.cc by handler::ha_open(). The server opens all tables by
+  calling ha_open() which then calls the handler specific open().
+*/
+int ha_example::open(const char *name, int mode, uint test_if_locked)
+{
+  DBUG_ENTER("ha_example::open");
+
+  if (!(share = get_share(name, table)))
+    DBUG_RETURN(1);
+  thr_lock_data_init(&share->lock,&lock,NULL);
+
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Closes a table. We call the free_share() function to free any resources
+  that we have allocated in the "shared" structure.
+
+  Called from sql_base.cc, sql_select.cc, and table.cc.
+  In sql_select.cc it is only used to close up temporary tables or during
+  the process where a temporary table is converted over to being a
+  myisam table.
+  For sql_base.cc look at close_data_tables().
+*/
+int ha_example::close(void)
+{
+  DBUG_ENTER("ha_example::close");
+  DBUG_RETURN(free_share(share));
+}
+
+
+/*
+  write_row() inserts a row. No extra() hint is given currently if a bulk load
+  is happeneding. buf() is a byte array of data. You can use the field
+  information to extract the data from the native byte array type.
+  Example of this would be:
+  for (Field **field=table->field ; *field ; field++)
+  {
+    ...
+  }
+
+  See ha_tina.cc for an example of extracting all of the data as strings.
+  ha_berekly.cc has an example of how to store it intact by "packing" it
+  for ha_berkeley's own native storage type.
+
+  See the note for update_row() on auto_increments and timestamps. This
+  case also applied to write_row().
+
+  Called from item_sum.cc, item_sum.cc, sql_acl.cc, sql_insert.cc,
+  sql_insert.cc, sql_select.cc, sql_table.cc, sql_udf.cc, and sql_update.cc.
+*/
+int ha_example::write_row(byte * buf)
+{
+  DBUG_ENTER("ha_example::write_row");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  Yes, update_row() does what you expect, it updates a row. old_data will have
+  the previous row record in it, while new_data will have the newest data in
+  it.
+  Keep in mind that the server can do updates based on ordering if an ORDER BY
+  clause was used. Consecutive ordering is not guarenteed.
+  Currently new_data will not have an updated auto_increament record, or
+  and updated timestamp field. You can do these for example by doing these:
+  if (table->timestamp_field_type & TIMESTAMP_AUTO_SET_ON_UPDATE)
+    table->timestamp_field->set_time();
+  if (table->next_number_field && record == table->record[0])
+    update_auto_increment();
+
+  Called from sql_select.cc, sql_acl.cc, sql_update.cc, and sql_insert.cc.
+*/
+int ha_example::update_row(const byte * old_data, byte * new_data)
+{
+
+  DBUG_ENTER("ha_example::update_row");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  This will delete a row. buf will contain a copy of the row to be deleted.
+  The server will call this right after the current row has been called (from
+  either a previous rnd_nexT() or index call).
+  If you keep a pointer to the last row or can access a primary key it will
+  make doing the deletion quite a bit easier.
+  Keep in mind that the server does no guarentee consecutive deletions. ORDER BY
+  clauses can be used.
+
+  Called in sql_acl.cc and sql_udf.cc to manage internal table information.
+  Called in sql_delete.cc, sql_insert.cc, and sql_select.cc. In sql_select it is
+  used for removing duplicates while in insert it is used for REPLACE calls.
+*/
+int ha_example::delete_row(const byte * buf)
+{
+  DBUG_ENTER("ha_example::delete_row");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  Positions an index cursor to the index specified in the handle. Fetches the
+  row if available. If the key value is null, begin at the first key of the
+  index.
+*/
+int ha_example::index_read(byte * buf, const byte * key,
+                           uint key_len __attribute__((unused)),
+                           enum ha_rkey_function find_flag
+                           __attribute__((unused)))
+{
+  DBUG_ENTER("ha_example::index_read");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  Positions an index cursor to the index specified in key. Fetches the
+  row if any.  This is only used to read whole keys.
+*/
+int ha_example::index_read_idx(byte * buf, uint index, const byte * key,
+                               uint key_len __attribute__((unused)),
+                               enum ha_rkey_function find_flag
+                               __attribute__((unused)))
+{
+  DBUG_ENTER("ha_example::index_read_idx");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  Used to read forward through the index.
+*/
+int ha_example::index_next(byte * buf)
+{
+  DBUG_ENTER("ha_example::index_next");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  Used to read backwards through the index.
+*/
+int ha_example::index_prev(byte * buf)
+{
+  DBUG_ENTER("ha_example::index_prev");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  index_first() asks for the first key in the index.
+
+  Called from opt_range.cc, opt_sum.cc, sql_handler.cc,
+  and sql_select.cc.
+*/
+int ha_example::index_first(byte * buf)
+{
+  DBUG_ENTER("ha_example::index_first");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  index_last() asks for the last key in the index.
+
+  Called from opt_range.cc, opt_sum.cc, sql_handler.cc,
+  and sql_select.cc.
+*/
+int ha_example::index_last(byte * buf)
+{
+  DBUG_ENTER("ha_example::index_last");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  rnd_init() is called when the system wants the storage engine to do a table
+  scan.
+  See the example in the introduction at the top of this file to see when
+  rnd_init() is called.
+
+  Called from filesort.cc, records.cc, sql_handler.cc, sql_select.cc, sql_table.cc,
+  and sql_update.cc.
+*/
+int ha_example::rnd_init(bool scan)
+{
+  DBUG_ENTER("ha_example::rnd_init");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+int ha_example::rnd_end()
+{
+  DBUG_ENTER("ha_example::rnd_end");
+  DBUG_RETURN(0);
+}
+
+/*
+  This is called for each row of the table scan. When you run out of records
+  you should return HA_ERR_END_OF_FILE. Fill buff up with the row information.
+  The Field structure for the table is the key to getting data into buf
+  in a manner that will allow the server to understand it.
+
+  Called from filesort.cc, records.cc, sql_handler.cc, sql_select.cc, sql_table.cc,
+  and sql_update.cc.
+*/
+int ha_example::rnd_next(byte *buf)
+{
+  DBUG_ENTER("ha_example::rnd_next");
+  DBUG_RETURN(HA_ERR_END_OF_FILE);
+}
+
+
+/*
+  position() is called after each call to rnd_next() if the data needs
+  to be ordered. You can do something like the following to store
+  the position:
+  my_store_ptr(ref, ref_length, current_position);
+
+  The server uses ref to store data. ref_length in the above case is
+  the size needed to store current_position. ref is just a byte array
+  that the server will maintain. If you are using offsets to mark rows, then
+  current_position should be the offset. If it is a primary key like in
+  BDB, then it needs to be a primary key.
+
+  Called from filesort.cc, sql_select.cc, sql_delete.cc and sql_update.cc.
+*/
+void ha_example::position(const byte *record)
+{
+  DBUG_ENTER("ha_example::position");
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  This is like rnd_next, but you are given a position to use
+  to determine the row. The position will be of the type that you stored in
+  ref. You can use ha_get_ptr(pos,ref_length) to retrieve whatever key
+  or position you saved when position() was called.
+  Called from filesort.cc records.cc sql_insert.cc sql_select.cc sql_update.cc.
+*/
+int ha_example::rnd_pos(byte * buf, byte *pos)
+{
+  DBUG_ENTER("ha_example::rnd_pos");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  ::info() is used to return information to the optimizer.
+  see my_base.h for the complete description
+
+  Currently this table handler doesn't implement most of the fields
+  really needed. SHOW also makes use of this data
+  Another note, you will probably want to have the following in your
+  code:
+  if (records < 2)
+    records = 2;
+  The reason is that the server will optimize for cases of only a single
+  record. If in a table scan you don't know the number of records
+  it will probably be better to set records to two so you can return
+  as many records as you need.
+  Along with records a few more variables you may wish to set are:
+    records
+    deleted
+    data_file_length
+    index_file_length
+    delete_length
+    check_time
+  Take a look at the public variables in handler.h for more information.
+
+  Called in:
+    filesort.cc
+    ha_heap.cc
+    item_sum.cc
+    opt_sum.cc
+    sql_delete.cc
+    sql_delete.cc
+    sql_derived.cc
+    sql_select.cc
+    sql_select.cc
+    sql_select.cc
+    sql_select.cc
+    sql_select.cc
+    sql_show.cc
+    sql_show.cc
+    sql_show.cc
+    sql_show.cc
+    sql_table.cc
+    sql_union.cc
+    sql_update.cc
+
+*/
+void ha_example::info(uint flag)
+{
+  DBUG_ENTER("ha_example::info");
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  extra() is called whenever the server wishes to send a hint to
+  the storage engine. The myisam engine implements the most hints.
+  ha_innodb.cc has the most exhaustive list of these hints.
+*/
+int ha_example::extra(enum ha_extra_function operation)
+{
+  DBUG_ENTER("ha_example::extra");
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Deprecated and likely to be removed in the future. Storage engines normally
+  just make a call like:
+  ha_example::extra(HA_EXTRA_RESET);
+  to handle it.
+*/
+int ha_example::reset(void)
+{
+  DBUG_ENTER("ha_example::reset");
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Used to delete all rows in a table. Both for cases of truncate and
+  for cases where the optimizer realizes that all rows will be
+  removed as a result of a SQL statement.
+
+  Called from item_sum.cc by Item_func_group_concat::clear(),
+  Item_sum_count_distinct::clear(), and Item_func_group_concat::clear().
+  Called from sql_delete.cc by mysql_delete().
+  Called from sql_select.cc by JOIN::reinit().
+  Called from sql_union.cc by st_select_lex_unit::exec().
+*/
+int ha_example::delete_all_rows()
+{
+  DBUG_ENTER("ha_example::delete_all_rows");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+
+/*
+  First you should go read the section "locking functions for mysql" in
+  lock.cc to understand this.
+  This create a lock on the table. If you are implementing a storage engine
+  that can handle transacations look at ha_berkely.cc to see how you will
+  want to goo about doing this. Otherwise you should consider calling flock()
+  here.
+
+  Called from lock.cc by lock_external() and unlock_external(). Also called
+  from sql_table.cc by copy_data_between_tables().
+*/
+int ha_example::external_lock(THD *thd, int lock_type)
+{
+  DBUG_ENTER("ha_example::external_lock");
+  DBUG_RETURN(0);
+}
+
+
+/*
+  The idea with handler::store_lock() is the following:
+
+  The statement decided which locks we should need for the table
+  for updates/deletes/inserts we get WRITE locks, for SELECT... we get
+  read locks.
+
+  Before adding the lock into the table lock handler (see thr_lock.c)
+  mysqld calls store lock with the requested locks.  Store lock can now
+  modify a write lock to a read lock (or some other lock), ignore the
+  lock (if we don't want to use MySQL table locks at all) or add locks
+  for many tables (like we do when we are using a MERGE handler).
+
+  Berkeley DB for example  changes all WRITE locks to TL_WRITE_ALLOW_WRITE
+  (which signals that we are doing WRITES, but we are still allowing other
+  reader's and writer's.
+
+  When releasing locks, store_lock() are also called. In this case one
+  usually doesn't have to do anything.
+
+  In some exceptional cases MySQL may send a request for a TL_IGNORE;
+  This means that we are requesting the same lock as last time and this
+  should also be ignored. (This may happen when someone does a flush
+  table when we have opened a part of the tables, in which case mysqld
+  closes and reopens the tables and tries to get the same locks at last
+  time).  In the future we will probably try to remove this.
+
+  Called from lock.cc by get_lock_data().
+*/
+THR_LOCK_DATA **ha_example::store_lock(THD *thd,
+                                       THR_LOCK_DATA **to,
+                                       enum thr_lock_type lock_type)
+{
+  if (lock_type != TL_IGNORE && lock.type == TL_UNLOCK)
+    lock.type=lock_type;
+  *to++= &lock;
+  return to;
+}
+
+/*
+  Used to delete a table. By the time delete_table() has been called all
+  opened references to this table will have been closed (and your globally
+  shared references released. The variable name will just be the name of
+  the table. You will need to remove any files you have created at this point.
+
+  If you do not implement this, the default delete_table() is called from
+  handler.cc and it will delete all files with the file extentions returned
+  by bas_ext().
+
+  Called from handler.cc by delete_table and  ha_create_table(). Only used
+  during create if the table_flag HA_DROP_BEFORE_CREATE was specified for
+  the storage engine.
+*/
+int ha_example::delete_table(const char *name)
+{
+  DBUG_ENTER("ha_example::delete_table");
+  /* This is not implemented but we want someone to be able that it works. */
+  DBUG_RETURN(0);
+}
+
+/*
+  Renames a table from one name to another from alter table call.
+
+  If you do not implement this, the default rename_table() is called from
+  handler.cc and it will delete all files with the file extentions returned
+  by bas_ext().
+
+  Called from sql_table.cc by mysql_rename_table().
+*/
+int ha_example::rename_table(const char * from, const char * to)
+{
+  DBUG_ENTER("ha_example::rename_table ");
+  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+}
+
+/*
+  Given a starting key, and an ending key estimate the number of rows that
+  will exist between the two. end_key may be empty which in case determine
+  if start_key matches any rows.
+
+  Called from opt_range.cc by check_quick_keys().
+*/
+ha_rows ha_example::records_in_range(uint inx, key_range *min_key,
+                                     key_range *max_key)
+{
+  DBUG_ENTER("ha_example::records_in_range");
+  DBUG_RETURN(10);                         // low number to force index usage
+}
+
+
+/*
+  create() is called to create a database. The variable name will have the name
+  of the table. When create() is called you do not need to worry about opening
+  the table. Also, the FRM file will have already been created so adjusting
+  create_info will not do you any good. You can overwrite the frm file at this
+  point if you wish to change the table definition, but there are no methods
+  currently provided for doing that.
+
+  Called from handle.cc by ha_create_table().
+*/
+int ha_example::create(const char *name, TABLE *table_arg,
+                       HA_CREATE_INFO *create_info)
+{
+  DBUG_ENTER("ha_example::create");
+  /* This is not implemented but we want someone to be able that it works. */
+  DBUG_RETURN(0);
+}
+
+mysql_declare_plugin
+{
+  MYSQL_STORAGE_ENGINE_PLUGIN,
+  &example_hton,
+  example_hton.name,
+  0x01000000 /* 1.0.0 */,
+  "Brian Aker, MySQL AB",
+  "Example Storage Engine",
+  tina_init_func, /* Plugin Init */
+  tina_done_func  /* Plugin Deinit */
+}
+mysql_declare_plugin_end;
+
diff --git a/storage/example/ha_example.h b/storage/example/ha_example.h
new file mode 100644
index 00000000000..139a50a3281
--- /dev/null
+++ b/storage/example/ha_example.h
@@ -0,0 +1,155 @@
+/* Copyright (C) 2003 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 */
+
+/*
+  Please read ha_exmple.cc before reading this file.
+  Please keep in mind that the example storage engine implements all methods
+  that are required to be implemented. handler.h has a full list of methods
+  that you can implement.
+*/
+
+#ifdef USE_PRAGMA_INTERFACE
+#pragma interface			/* gcc class implementation */
+#endif
+
+/*
+  EXAMPLE_SHARE is a structure that will be shared amoung all open handlers
+  The example implements the minimum of what you will probably need.
+*/
+typedef struct st_example_share {
+  char *table_name;
+  uint table_name_length,use_count;
+  pthread_mutex_t mutex;
+  THR_LOCK lock;
+} EXAMPLE_SHARE;
+
+/*
+  Class definition for the storage engine
+*/
+class ha_example: public handler
+{
+  THR_LOCK_DATA lock;      /* MySQL lock */
+  EXAMPLE_SHARE *share;    /* Shared lock info */
+
+public:
+  ha_example(TABLE_SHARE *table_arg);
+  ~ha_example()
+  {
+  }
+  /* The name that will be used for display purposes */
+  const char *table_type() const { return "EXAMPLE"; }
+  /*
+    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 inx) { return "HASH"; }
+  const char **bas_ext() const;
+  /*
+    This is a list of flags that says what the storage engine
+    implements. The current table flags are documented in
+    handler.h
+  */
+  ulong table_flags() const
+  {
+    return 0;
+  }
+  /*
+    This is a bitmap of flags that says how the storage engine
+    implements indexes. The current index flags are documented in
+    handler.h. If you do not implement indexes, just return zero
+    here.
+
+    part is the key part to check. First key part is 0
+    If all_parts it's set, MySQL want to know the flags for the combined
+    index up to and including 'part'.
+  */
+  ulong index_flags(uint inx, uint part, bool all_parts) const
+  {
+    return 0;
+  }
+  /*
+    unireg.cc will call the following to make sure that the storage engine can
+    handle the data it is about to send.
+
+    Return *real* limits of your storage engine here. MySQL will do
+    min(your_limits, MySQL_limits) automatically
+
+    There is no need to implement ..._key_... methods if you don't suport
+    indexes.
+  */
+  uint max_supported_record_length() const { return HA_MAX_REC_LENGTH; }
+  uint max_supported_keys()          const { return 0; }
+  uint max_supported_key_parts()     const { return 0; }
+  uint max_supported_key_length()    const { return 0; }
+  /*
+    Called in test_quick_select to determine if indexes should be used.
+  */
+  virtual double scan_time() { return (double) (records+deleted) / 20.0+10; }
+  /*
+    The next method will never be called if you do not implement indexes.
+  */
+  virtual double read_time(ha_rows rows) { return (double) rows /  20.0+1; }
+
+  /*
+    Everything below are methods that we implment in ha_example.cc.
+
+    Most of these methods are not obligatory, skip them and
+    MySQL will treat them as not implemented
+  */
+  int open(const char *name, int mode, uint test_if_locked);    // required
+  int close(void);                                              // required
+
+  int write_row(byte * buf);
+  int update_row(const byte * old_data, byte * new_data);
+  int delete_row(const byte * buf);
+  int index_read(byte * buf, const byte * key,
+                 uint key_len, enum ha_rkey_function find_flag);
+  int index_read_idx(byte * buf, uint idx, const byte * key,
+                     uint key_len, enum ha_rkey_function find_flag);
+  int index_next(byte * buf);
+  int index_prev(byte * buf);
+  int index_first(byte * buf);
+  int index_last(byte * buf);
+  /*
+    unlike index_init(), rnd_init() can be called two times
+    without rnd_end() in between (it only makes sense if scan=1).
+    then the second call should prepare for the new table scan
+    (e.g if rnd_init allocates the cursor, second call should
+    position it to the start of the table, no need to deallocate
+    and allocate it again
+  */
+  int rnd_init(bool scan);                                      //required
+  int rnd_end();
+  int rnd_next(byte *buf);                                      //required
+  int rnd_pos(byte * buf, byte *pos);                           //required
+  void position(const byte *record);                            //required
+  void info(uint);                                              //required
+
+  int extra(enum ha_extra_function operation);
+  int reset(void);
+  int external_lock(THD *thd, int lock_type);                   //required
+  int delete_all_rows(void);
+  ha_rows records_in_range(uint inx, key_range *min_key,
+                           key_range *max_key);
+  int delete_table(const char *from);
+  int rename_table(const char * from, const char * to);
+  int create(const char *name, TABLE *form,
+             HA_CREATE_INFO *create_info);                      //required
+
+  THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
+                             enum thr_lock_type lock_type);     //required
+};
+