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9a92325c02
Adding support to allow engines to tell what formats they can handle. The server will generate an error if it is not possible to log the statement according to the logging mode in effect. Adding flags to several storage engines to state what they can handle. Changes to NDB handler removing code that forces row-based mode and adding flag saying that NDB can only handle row format. Adding check that binlog flags are only used for real tables that are opened for writing.
251 lines
8.6 KiB
C++
251 lines
8.6 KiB
C++
/* Copyright (C) 2003 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/** @file ha_example.h
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@brief
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The ha_example engine is a stubbed storage engine for example purposes only;
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it does nothing at this point. Its purpose is to provide a source
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code illustration of how to begin writing new storage engines; see also
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/storage/example/ha_example.cc.
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@note
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Please read ha_example.cc before reading this file.
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Reminder: The example storage engine implements all methods that are *required*
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to be implemented. For a full list of all methods that you can implement, see
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handler.h.
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@see
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/sql/handler.h and /storage/example/ha_example.cc
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*/
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#ifdef USE_PRAGMA_INTERFACE
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#pragma interface /* gcc class implementation */
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#endif
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/** @brief
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EXAMPLE_SHARE is a structure that will be shared among all open handlers.
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This example implements the minimum of what you will probably need.
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*/
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typedef struct st_example_share {
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char *table_name;
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uint table_name_length,use_count;
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pthread_mutex_t mutex;
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THR_LOCK lock;
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} EXAMPLE_SHARE;
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/** @brief
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Class definition for the storage engine
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*/
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class ha_example: public handler
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{
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THR_LOCK_DATA lock; ///< MySQL lock
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EXAMPLE_SHARE *share; ///< Shared lock info
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public:
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ha_example(handlerton *hton, TABLE_SHARE *table_arg);
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~ha_example()
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{
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}
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/** @brief
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The name that will be used for display purposes.
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*/
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const char *table_type() const { return "EXAMPLE"; }
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/** @brief
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The name of the index type that will be used for display.
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Don't implement this method unless you really have indexes.
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*/
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const char *index_type(uint inx) { return "HASH"; }
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/** @brief
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The file extensions.
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*/
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const char **bas_ext() const;
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/** @brief
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This is a list of flags that indicate what functionality the storage engine
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implements. The current table flags are documented in handler.h
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*/
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ulonglong table_flags() const
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{
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/*
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We are saying that this engine is just row capable to have an
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engine that can only handle row-based logging. This is used in
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testing.
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*/
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return HA_BINLOG_ROW_CAPABLE;
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}
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/** @brief
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This is a bitmap of flags that indicates how the storage engine
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implements indexes. The current index flags are documented in
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handler.h. If you do not implement indexes, just return zero here.
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@details
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part is the key part to check. First key part is 0.
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If all_parts is set, MySQL wants to know the flags for the combined
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index, up to and including 'part'.
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*/
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ulong index_flags(uint inx, uint part, bool all_parts) const
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{
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return 0;
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}
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/** @brief
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unireg.cc will call max_supported_record_length(), max_supported_keys(),
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max_supported_key_parts(), uint max_supported_key_length()
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to make sure that the storage engine can handle the data it is about to
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send. Return *real* limits of your storage engine here; MySQL will do
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min(your_limits, MySQL_limits) automatically.
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*/
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uint max_supported_record_length() const { return HA_MAX_REC_LENGTH; }
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/** @brief
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unireg.cc will call this to make sure that the storage engine can handle
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the data it is about to send. Return *real* limits of your storage engine
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here; MySQL will do min(your_limits, MySQL_limits) automatically.
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@details
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There is no need to implement ..._key_... methods if your engine doesn't
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support indexes.
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*/
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uint max_supported_keys() const { return 0; }
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/** @brief
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unireg.cc will call this to make sure that the storage engine can handle
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the data it is about to send. Return *real* limits of your storage engine
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here; MySQL will do min(your_limits, MySQL_limits) automatically.
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@details
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There is no need to implement ..._key_... methods if your engine doesn't
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support indexes.
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*/
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uint max_supported_key_parts() const { return 0; }
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/** @brief
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unireg.cc will call this to make sure that the storage engine can handle
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the data it is about to send. Return *real* limits of your storage engine
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here; MySQL will do min(your_limits, MySQL_limits) automatically.
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@details
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There is no need to implement ..._key_... methods if your engine doesn't
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support indexes.
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*/
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uint max_supported_key_length() const { return 0; }
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/** @brief
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Called in test_quick_select to determine if indexes should be used.
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*/
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virtual double scan_time() { return (double) (stats.records+stats.deleted) / 20.0+10; }
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/** @brief
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This method will never be called if you do not implement indexes.
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*/
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virtual double read_time(ha_rows rows) { return (double) rows / 20.0+1; }
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/*
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Everything below are methods that we implement in ha_example.cc.
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Most of these methods are not obligatory, skip them and
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MySQL will treat them as not implemented
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*/
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/** @brief
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We implement this in ha_example.cc; it's a required method.
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*/
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int open(const char *name, int mode, uint test_if_locked); // required
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/** @brief
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We implement this in ha_example.cc; it's a required method.
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*/
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int close(void); // required
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int write_row(byte * buf);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int update_row(const byte * old_data, byte * new_data);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int delete_row(const byte * buf);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int index_read(byte * buf, const byte * key,
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key_part_map keypart_map, enum ha_rkey_function find_flag);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int index_next(byte * buf);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int index_prev(byte * buf);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int index_first(byte * buf);
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/** @brief
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We implement this in ha_example.cc. It's not an obligatory method;
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skip it and and MySQL will treat it as not implemented.
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*/
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int index_last(byte * buf);
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/** @brief
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Unlike index_init(), rnd_init() can be called two consecutive times
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without rnd_end() in between (it only makes sense if scan=1). In this
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case, the second call should prepare for the new table scan (e.g if
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rnd_init() allocates the cursor, the second call should position the
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cursor to the start of the table; no need to deallocate and allocate
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it again. This is a required method.
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*/
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int rnd_init(bool scan); //required
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int rnd_end();
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int rnd_next(byte *buf); ///< required
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int rnd_pos(byte * buf, byte *pos); ///< required
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void position(const byte *record); ///< required
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int info(uint); ///< required
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int extra(enum ha_extra_function operation);
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int external_lock(THD *thd, int lock_type); ///< required
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int delete_all_rows(void);
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ha_rows records_in_range(uint inx, key_range *min_key,
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key_range *max_key);
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int delete_table(const char *from);
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int rename_table(const char * from, const char * to);
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int create(const char *name, TABLE *form,
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HA_CREATE_INFO *create_info); ///< required
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THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
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enum thr_lock_type lock_type); ///< required
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};
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