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- Committer: Monty Taylor
- Date: 2009-11-13 18:55:43 UTC
- mfrom: (1215 staging)
- mto: (1220.1.1 staging) (1192.7.1 pandora-build) (1238.2.1 build) (1240.1.5 build)
- mto: This revision was merged to the branch mainline in revision 1221.
- Revision ID: mordred@inaugust.com-20091113185543-a8pytco81m75v6m0
Merged trunk.
- files added:
- drizzled/ha_commands.cc
- files removed:
- plugin/information_engine/information_share.cc
- files modified:
- .bzrignore
added
removed
drizzled/ha_commands.cc
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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (C) 2008 Sun Microsystems
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*
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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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*
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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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*
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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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
21
@file Cursor.cc
22
23
Handler-calling-functions
24
*/
25
26
#include "drizzled/server_includes.h"
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#include "mysys/hash.h"
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#include "drizzled/error.h"
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#include "drizzled/gettext.h"
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#include "drizzled/probes.h"
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#include "drizzled/sql_parse.h"
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#include "drizzled/cost_vect.h"
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#include "drizzled/session.h"
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#include "drizzled/sql_base.h"
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#include "drizzled/replication_services.h"
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#include "drizzled/lock.h"
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#include "drizzled/item/int.h"
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#include "drizzled/item/empty_string.h"
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#include "drizzled/unireg.h" // for mysql_frm_type
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#include "drizzled/field/timestamp.h"
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#include "drizzled/message/table.pb.h"
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#include "drizzled/plugin/client.h"
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using namespace std;
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using namespace drizzled;
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KEY_CREATE_INFO default_key_create_info= { HA_KEY_ALG_UNDEF, 0, {NULL,0} };
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/* number of entries in storage_engines[] */
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uint32_t total_ha= 0;
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/* number of storage engines (from storage_engines[]) that support 2pc */
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uint32_t total_ha_2pc= 0;
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/* size of savepoint storage area (see ha_init) */
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uint32_t savepoint_alloc_size= 0;
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56
const char *ha_row_type[] = {
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"", "FIXED", "DYNAMIC", "COMPRESSED", "REDUNDANT", "COMPACT", "PAGE", "?","?","?"
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};
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const char *tx_isolation_names[] =
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{ "READ-UNCOMMITTED", "READ-COMMITTED", "REPEATABLE-READ", "SERIALIZABLE",
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NULL};
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TYPELIB tx_isolation_typelib= {array_elements(tx_isolation_names)-1,"",
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tx_isolation_names, NULL};
66
67
68
/**
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Register Cursor error messages for use with my_error().
70
71
@retval
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0 OK
73
@retval
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!=0 Error
75
*/
76
77
int ha_init_errors(void)
78
{
79
#define SETMSG(nr, msg) errmsgs[(nr) - HA_ERR_FIRST]= (msg)
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const char **errmsgs;
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82
/* Allocate a pointer array for the error message strings. */
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/* Zerofill it to avoid uninitialized gaps. */
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if (! (errmsgs= (const char**) malloc(HA_ERR_ERRORS * sizeof(char*))))
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return 1;
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memset(errmsgs, 0, HA_ERR_ERRORS * sizeof(char *));
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/* Set the dedicated error messages. */
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SETMSG(HA_ERR_KEY_NOT_FOUND, ER(ER_KEY_NOT_FOUND));
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SETMSG(HA_ERR_FOUND_DUPP_KEY, ER(ER_DUP_KEY));
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SETMSG(HA_ERR_RECORD_CHANGED, "Update wich is recoverable");
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SETMSG(HA_ERR_WRONG_INDEX, "Wrong index given to function");
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SETMSG(HA_ERR_CRASHED, ER(ER_NOT_KEYFILE));
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SETMSG(HA_ERR_WRONG_IN_RECORD, ER(ER_CRASHED_ON_USAGE));
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SETMSG(HA_ERR_OUT_OF_MEM, "Table Cursor out of memory");
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SETMSG(HA_ERR_NOT_A_TABLE, "Incorrect file format '%.64s'");
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SETMSG(HA_ERR_WRONG_COMMAND, "Command not supported");
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SETMSG(HA_ERR_OLD_FILE, ER(ER_OLD_KEYFILE));
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SETMSG(HA_ERR_NO_ACTIVE_RECORD, "No record read in update");
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SETMSG(HA_ERR_RECORD_DELETED, "Intern record deleted");
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SETMSG(HA_ERR_RECORD_FILE_FULL, ER(ER_RECORD_FILE_FULL));
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SETMSG(HA_ERR_INDEX_FILE_FULL, "No more room in index file '%.64s'");
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SETMSG(HA_ERR_END_OF_FILE, "End in next/prev/first/last");
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SETMSG(HA_ERR_UNSUPPORTED, ER(ER_ILLEGAL_HA));
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SETMSG(HA_ERR_TO_BIG_ROW, "Too big row");
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SETMSG(HA_WRONG_CREATE_OPTION, "Wrong create option");
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SETMSG(HA_ERR_FOUND_DUPP_UNIQUE, ER(ER_DUP_UNIQUE));
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SETMSG(HA_ERR_UNKNOWN_CHARSET, "Can't open charset");
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SETMSG(HA_ERR_WRONG_MRG_TABLE_DEF, ER(ER_WRONG_MRG_TABLE));
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SETMSG(HA_ERR_CRASHED_ON_REPAIR, ER(ER_CRASHED_ON_REPAIR));
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SETMSG(HA_ERR_CRASHED_ON_USAGE, ER(ER_CRASHED_ON_USAGE));
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SETMSG(HA_ERR_LOCK_WAIT_TIMEOUT, ER(ER_LOCK_WAIT_TIMEOUT));
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SETMSG(HA_ERR_LOCK_TABLE_FULL, ER(ER_LOCK_TABLE_FULL));
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SETMSG(HA_ERR_READ_ONLY_TRANSACTION, ER(ER_READ_ONLY_TRANSACTION));
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SETMSG(HA_ERR_LOCK_DEADLOCK, ER(ER_LOCK_DEADLOCK));
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SETMSG(HA_ERR_CANNOT_ADD_FOREIGN, ER(ER_CANNOT_ADD_FOREIGN));
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SETMSG(HA_ERR_NO_REFERENCED_ROW, ER(ER_NO_REFERENCED_ROW_2));
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SETMSG(HA_ERR_ROW_IS_REFERENCED, ER(ER_ROW_IS_REFERENCED_2));
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SETMSG(HA_ERR_NO_SAVEPOINT, "No savepoint with that name");
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SETMSG(HA_ERR_NON_UNIQUE_BLOCK_SIZE, "Non unique key block size");
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SETMSG(HA_ERR_NO_SUCH_TABLE, "No such table: '%.64s'");
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SETMSG(HA_ERR_TABLE_EXIST, ER(ER_TABLE_EXISTS_ERROR));
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SETMSG(HA_ERR_NO_CONNECTION, "Could not connect to storage engine");
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SETMSG(HA_ERR_TABLE_DEF_CHANGED, ER(ER_TABLE_DEF_CHANGED));
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SETMSG(HA_ERR_FOREIGN_DUPLICATE_KEY, "FK constraint would lead to duplicate key");
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SETMSG(HA_ERR_TABLE_NEEDS_UPGRADE, ER(ER_TABLE_NEEDS_UPGRADE));
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SETMSG(HA_ERR_TABLE_READONLY, ER(ER_OPEN_AS_READONLY));
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SETMSG(HA_ERR_AUTOINC_READ_FAILED, ER(ER_AUTOINC_READ_FAILED));
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SETMSG(HA_ERR_AUTOINC_ERANGE, ER(ER_WARN_DATA_OUT_OF_RANGE));
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/* Register the error messages for use with my_error(). */
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return my_error_register(errmsgs, HA_ERR_FIRST, HA_ERR_LAST);
133
}
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/**
137
Unregister Cursor error messages.
138
139
@retval
140
0 OK
141
@retval
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!=0 Error
143
*/
144
static int ha_finish_errors(void)
145
{
146
const char **errmsgs;
147
148
/* Allocate a pointer array for the error message strings. */
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if (! (errmsgs= my_error_unregister(HA_ERR_FIRST, HA_ERR_LAST)))
150
return 1;
151
free((unsigned char*) errmsgs);
152
return 0;
153
}
154
155
int ha_init()
156
{
157
int error= 0;
158
159
assert(total_ha < MAX_HA);
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/*
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Check if there is a transaction-capable storage engine besides the
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binary log (which is considered a transaction-capable storage engine in
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counting total_ha)
164
*/
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savepoint_alloc_size+= sizeof(SAVEPOINT);
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return error;
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}
168
169
int ha_end()
170
{
171
int error= 0;
172
173
/*
174
This should be eventualy based on the graceful shutdown flag.
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So if flag is equal to HA_PANIC_CLOSE, the deallocate
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the errors.
177
*/
178
if (ha_finish_errors())
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error= 1;
180
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return error;
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}
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/* ========================================================================
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======================= TRANSACTIONS ===================================*/
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/**
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Transaction handling in the server
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==================================
192
193
In each client connection, MySQL maintains two transactional
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states:
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- a statement transaction,
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- a standard, also called normal transaction.
197
198
Historical note
199
---------------
200
"Statement transaction" is a non-standard term that comes
201
from the times when MySQL supported BerkeleyDB storage engine.
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203
First of all, it should be said that in BerkeleyDB auto-commit
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mode auto-commits operations that are atomic to the storage
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engine itself, such as a write of a record, and are too
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high-granular to be atomic from the application perspective
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(MySQL). One SQL statement could involve many BerkeleyDB
208
auto-committed operations and thus BerkeleyDB auto-commit was of
209
little use to MySQL.
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211
Secondly, instead of SQL standard savepoints, BerkeleyDB
212
provided the concept of "nested transactions". In a nutshell,
213
transactions could be arbitrarily nested, but when the parent
214
transaction was committed or aborted, all its child (nested)
215
transactions were handled committed or aborted as well.
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Commit of a nested transaction, in turn, made its changes
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visible, but not durable: it destroyed the nested transaction,
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all its changes would become available to the parent and
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currently active nested transactions of this parent.
220
221
So the mechanism of nested transactions was employed to
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provide "all or nothing" guarantee of SQL statements
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required by the standard.
224
A nested transaction would be created at start of each SQL
225
statement, and destroyed (committed or aborted) at statement
226
end. Such nested transaction was internally referred to as
227
a "statement transaction" and gave birth to the term.
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229
<Historical note ends>
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231
Since then a statement transaction is started for each statement
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that accesses transactional tables or uses the binary log. If
233
the statement succeeds, the statement transaction is committed.
234
If the statement fails, the transaction is rolled back. Commits
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of statement transactions are not durable -- each such
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transaction is nested in the normal transaction, and if the
237
normal transaction is rolled back, the effects of all enclosed
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statement transactions are undone as well. Technically,
239
a statement transaction can be viewed as a savepoint which is
240
maintained automatically in order to make effects of one
241
statement atomic.
242
243
The normal transaction is started by the user and is ended
244
usually upon a user request as well. The normal transaction
245
encloses transactions of all statements issued between
246
its beginning and its end.
247
In autocommit mode, the normal transaction is equivalent
248
to the statement transaction.
249
250
Since MySQL supports PSEA (pluggable storage engine
251
architecture), more than one transactional engine can be
252
active at a time. Hence transactions, from the server
253
point of view, are always distributed. In particular,
254
transactional state is maintained independently for each
255
engine. In order to commit a transaction the two phase
256
commit protocol is employed.
257
258
Not all statements are executed in context of a transaction.
259
Administrative and status information statements do not modify
260
engine data, and thus do not start a statement transaction and
261
also have no effect on the normal transaction. Examples of such
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statements are SHOW STATUS and RESET SLAVE.
263
264
Similarly DDL statements are not transactional,
265
and therefore a transaction is [almost] never started for a DDL
266
statement. The difference between a DDL statement and a purely
267
administrative statement though is that a DDL statement always
268
commits the current transaction before proceeding, if there is
269
any.
270
271
At last, SQL statements that work with non-transactional
272
engines also have no effect on the transaction state of the
273
connection. Even though they are written to the binary log,
274
and the binary log is, overall, transactional, the writes
275
are done in "write-through" mode, directly to the binlog
276
file, followed with a OS cache sync, in other words,
277
bypassing the binlog undo log (translog).
278
They do not commit the current normal transaction.
279
A failure of a statement that uses non-transactional tables
280
would cause a rollback of the statement transaction, but
281
in case there no non-transactional tables are used,
282
no statement transaction is started.
283
284
Data layout
285
-----------
286
287
The server stores its transaction-related data in
288
session->transaction. This structure has two members of type
289
Session_TRANS. These members correspond to the statement and
290
normal transactions respectively:
291
292
- session->transaction.stmt contains a list of engines
293
that are participating in the given statement
294
- session->transaction.all contains a list of engines that
295
have participated in any of the statement transactions started
296
within the context of the normal transaction.
297
Each element of the list contains a pointer to the storage
298
engine, engine-specific transactional data, and engine-specific
299
transaction flags.
300
301
In autocommit mode session->transaction.all is empty.
302
Instead, data of session->transaction.stmt is
303
used to commit/rollback the normal transaction.
304
305
The list of registered engines has a few important properties:
306
- no engine is registered in the list twice
307
- engines are present in the list a reverse temporal order --
308
new participants are always added to the beginning of the list.
309
310
Transaction life cycle
311
----------------------
312
313
When a new connection is established, session->transaction
314
members are initialized to an empty state.
315
If a statement uses any tables, all affected engines
316
are registered in the statement engine list. In
317
non-autocommit mode, the same engines are registered in
318
the normal transaction list.
319
At the end of the statement, the server issues a commit
320
or a roll back for all engines in the statement list.
321
At this point transaction flags of an engine, if any, are
322
propagated from the statement list to the list of the normal
323
transaction.
324
When commit/rollback is finished, the statement list is
325
cleared. It will be filled in again by the next statement,
326
and emptied again at the next statement's end.
327
328
The normal transaction is committed in a similar way
329
(by going over all engines in session->transaction.all list)
330
but at different times:
331
- upon COMMIT SQL statement is issued by the user
332
- implicitly, by the server, at the beginning of a DDL statement
333
or SET AUTOCOMMIT={0|1} statement.
334
335
The normal transaction can be rolled back as well:
336
- if the user has requested so, by issuing ROLLBACK SQL
337
statement
338
- if one of the storage engines requested a rollback
339
by setting session->transaction_rollback_request. This may
340
happen in case, e.g., when the transaction in the engine was
341
chosen a victim of the internal deadlock resolution algorithm
342
and rolled back internally. When such a situation happens, there
343
is little the server can do and the only option is to rollback
344
transactions in all other participating engines. In this case
345
the rollback is accompanied by an error sent to the user.
346
347
As follows from the use cases above, the normal transaction
348
is never committed when there is an outstanding statement
349
transaction. In most cases there is no conflict, since
350
commits of the normal transaction are issued by a stand-alone
351
administrative or DDL statement, thus no outstanding statement
352
transaction of the previous statement exists. Besides,
353
all statements that manipulate with the normal transaction
354
are prohibited in stored functions and triggers, therefore
355
no conflicting situation can occur in a sub-statement either.
356
The remaining rare cases when the server explicitly has
357
to commit the statement transaction prior to committing the normal
358
one cover error-handling scenarios (see for example
359
?).
360
361
When committing a statement or a normal transaction, the server
362
either uses the two-phase commit protocol, or issues a commit
363
in each engine independently. The two-phase commit protocol
364
is used only if:
365
- all participating engines support two-phase commit (provide
366
plugin::StorageEngine::prepare PSEA API call) and
367
- transactions in at least two engines modify data (i.e. are
368
not read-only).
369
370
Note that the two phase commit is used for
371
statement transactions, even though they are not durable anyway.
372
This is done to ensure logical consistency of data in a multiple-
373
engine transaction.
374
For example, imagine that some day MySQL supports unique
375
constraint checks deferred till the end of statement. In such
376
case a commit in one of the engines may yield ER_DUP_KEY,
377
and MySQL should be able to gracefully abort statement
378
transactions of other participants.
379
380
After the normal transaction has been committed,
381
session->transaction.all list is cleared.
382
383
When a connection is closed, the current normal transaction, if
384
any, is rolled back.
385
386
Roles and responsibilities
387
--------------------------
388
389
The server has no way to know that an engine participates in
390
the statement and a transaction has been started
391
in it unless the engine says so. Thus, in order to be
392
a part of a transaction, the engine must "register" itself.
393
This is done by invoking trans_register_ha() server call.
394
Normally the engine registers itself whenever Cursor::external_lock()
395
is called. trans_register_ha() can be invoked many times: if
396
an engine is already registered, the call does nothing.
397
In case autocommit is not set, the engine must register itself
398
twice -- both in the statement list and in the normal transaction
399
list.
400
In which list to register is a parameter of trans_register_ha().
401
402
Note, that although the registration interface in itself is
403
fairly clear, the current usage practice often leads to undesired
404
effects. E.g. since a call to trans_register_ha() in most engines
405
is embedded into implementation of Cursor::external_lock(), some
406
DDL statements start a transaction (at least from the server
407
point of view) even though they are not expected to. E.g.
408
CREATE TABLE does not start a transaction, since
409
Cursor::external_lock() is never called during CREATE TABLE. But
410
CREATE TABLE ... SELECT does, since Cursor::external_lock() is
411
called for the table that is being selected from. This has no
412
practical effects currently, but must be kept in mind
413
nevertheless.
414
415
Once an engine is registered, the server will do the rest
416
of the work.
417
418
During statement execution, whenever any of data-modifying
419
PSEA API methods is used, e.g. Cursor::write_row() or
420
Cursor::update_row(), the read-write flag is raised in the
421
statement transaction for the involved engine.
422
Currently All PSEA calls are "traced", and the data can not be
423
changed in a way other than issuing a PSEA call. Important:
424
unless this invariant is preserved the server will not know that
425
a transaction in a given engine is read-write and will not
426
involve the two-phase commit protocol!
427
428
At the end of a statement, server call
429
ha_autocommit_or_rollback() is invoked. This call in turn
430
invokes plugin::StorageEngine::prepare() for every involved engine.
431
Prepare is followed by a call to plugin::StorageEngine::commit_one_phase()
432
If a one-phase commit will suffice, plugin::StorageEngine::prepare() is not
433
invoked and the server only calls plugin::StorageEngine::commit_one_phase().
434
At statement commit, the statement-related read-write engine
435
flag is propagated to the corresponding flag in the normal
436
transaction. When the commit is complete, the list of registered
437
engines is cleared.
438
439
Rollback is handled in a similar fashion.
440
441
Additional notes on DDL and the normal transaction.
442
---------------------------------------------------
443
444
DDLs and operations with non-transactional engines
445
do not "register" in session->transaction lists, and thus do not
446
modify the transaction state. Besides, each DDL in
447
MySQL is prefixed with an implicit normal transaction commit
448
(a call to Session::endActiveTransaction()), and thus leaves nothing
449
to modify.
450
However, as it has been pointed out with CREATE TABLE .. SELECT,
451
some DDL statements can start a *new* transaction.
452
453
Behaviour of the server in this case is currently badly
454
defined.
455
DDL statements use a form of "semantic" logging
456
to maintain atomicity: if CREATE TABLE .. SELECT failed,
457
the newly created table is deleted.
458
In addition, some DDL statements issue interim transaction
459
commits: e.g. ALTER Table issues a commit after data is copied
460
from the original table to the internal temporary table. Other
461
statements, e.g. CREATE TABLE ... SELECT do not always commit
462
after itself.
463
And finally there is a group of DDL statements such as
464
RENAME/DROP Table that doesn't start a new transaction
465
and doesn't commit.
466
467
This diversity makes it hard to say what will happen if
468
by chance a stored function is invoked during a DDL --
469
whether any modifications it makes will be committed or not
470
is not clear. Fortunately, SQL grammar of few DDLs allows
471
invocation of a stored function.
472
473
A consistent behaviour is perhaps to always commit the normal
474
transaction after all DDLs, just like the statement transaction
475
is always committed at the end of all statements.
476
*/
477
478
/**
479
Register a storage engine for a transaction.
480
481
Every storage engine MUST call this function when it starts
482
a transaction or a statement (that is it must be called both for the
483
"beginning of transaction" and "beginning of statement").
484
Only storage engines registered for the transaction/statement
485
will know when to commit/rollback it.
486
487
@note
488
trans_register_ha is idempotent - storage engine may register many
489
times per transaction.
490
491
*/
492
void trans_register_ha(Session *session, bool all, plugin::StorageEngine *engine)
493
{
494
Session_TRANS *trans;
495
Ha_trx_info *ha_info;
496
497
if (all)
498
{
499
trans= &session->transaction.all;
500
session->server_status|= SERVER_STATUS_IN_TRANS;
501
}
502
else
503
trans= &session->transaction.stmt;
504
505
ha_info= session->ha_data[engine->getSlot()].ha_info + static_cast<unsigned>(all);
506
507
if (ha_info->is_started())
508
return; /* already registered, return */
509
510
ha_info->register_ha(trans, engine);
511
512
trans->no_2pc|= not engine->has_2pc();
513
if (session->transaction.xid_state.xid.is_null())
514
session->transaction.xid_state.xid.set(session->query_id);
515
}
516
517
/**
518
Check if we can skip the two-phase commit.
519
520
A helper function to evaluate if two-phase commit is mandatory.
521
As a side effect, propagates the read-only/read-write flags
522
of the statement transaction to its enclosing normal transaction.
523
524
@retval true we must run a two-phase commit. Returned
525
if we have at least two engines with read-write changes.
526
@retval false Don't need two-phase commit. Even if we have two
527
transactional engines, we can run two independent
528
commits if changes in one of the engines are read-only.
529
*/
530
531
static
532
bool
533
ha_check_and_coalesce_trx_read_only(Session *session, Ha_trx_info *ha_list,
534
bool all)
535
{
536
/* The number of storage engines that have actual changes. */
537
unsigned rw_ha_count= 0;
538
Ha_trx_info *ha_info;
539
540
for (ha_info= ha_list; ha_info; ha_info= ha_info->next())
541
{
542
if (ha_info->is_trx_read_write())
543
++rw_ha_count;
544
545
if (! all)
546
{
547
Ha_trx_info *ha_info_all= &session->ha_data[ha_info->engine()->getSlot()].ha_info[1];
548
assert(ha_info != ha_info_all);
549
/*
550
Merge read-only/read-write information about statement
551
transaction to its enclosing normal transaction. Do this
552
only if in a real transaction -- that is, if we know
553
that ha_info_all is registered in session->transaction.all.
554
Since otherwise we only clutter the normal transaction flags.
555
*/
556
if (ha_info_all->is_started()) /* false if autocommit. */
557
ha_info_all->coalesce_trx_with(ha_info);
558
}
559
else if (rw_ha_count > 1)
560
{
561
/*
562
It is a normal transaction, so we don't need to merge read/write
563
information up, and the need for two-phase commit has been
564
already established. Break the loop prematurely.
565
*/
566
break;
567
}
568
}
569
return rw_ha_count > 1;
570
}
571
572
573
/**
574
@retval
575
0 ok
576
@retval
577
1 transaction was rolled back
578
@retval
579
2 error during commit, data may be inconsistent
580
581
@todo
582
Since we don't support nested statement transactions in 5.0,
583
we can't commit or rollback stmt transactions while we are inside
584
stored functions or triggers. So we simply do nothing now.
585
TODO: This should be fixed in later ( >= 5.1) releases.
586
*/
587
int ha_commit_trans(Session *session, bool all)
588
{
589
int error= 0, cookie= 0;
590
/*
591
'all' means that this is either an explicit commit issued by
592
user, or an implicit commit issued by a DDL.
593
*/
594
Session_TRANS *trans= all ? &session->transaction.all : &session->transaction.stmt;
595
bool is_real_trans= all || session->transaction.all.ha_list == 0;
596
Ha_trx_info *ha_info= trans->ha_list;
597
598
/*
599
We must not commit the normal transaction if a statement
600
transaction is pending. Otherwise statement transaction
601
flags will not get propagated to its normal transaction's
602
counterpart.
603
*/
604
assert(session->transaction.stmt.ha_list == NULL ||
605
trans == &session->transaction.stmt);
606
607
if (ha_info)
608
{
609
bool must_2pc;
610
611
if (is_real_trans && wait_if_global_read_lock(session, 0, 0))
612
{
613
ha_rollback_trans(session, all);
614
return 1;
615
}
616
617
must_2pc= ha_check_and_coalesce_trx_read_only(session, ha_info, all);
618
619
if (!trans->no_2pc && must_2pc)
620
{
621
for (; ha_info && !error; ha_info= ha_info->next())
622
{
623
int err;
624
plugin::StorageEngine *engine= ha_info->engine();
625
/*
626
Do not call two-phase commit if this particular
627
transaction is read-only. This allows for simpler
628
implementation in engines that are always read-only.
629
*/
630
if (! ha_info->is_trx_read_write())
631
continue;
632
/*
633
Sic: we know that prepare() is not NULL since otherwise
634
trans->no_2pc would have been set.
635
*/
636
if ((err= engine->prepare(session, all)))
637
{
638
my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
639
error= 1;
640
}
641
status_var_increment(session->status_var.ha_prepare_count);
642
}
643
if (error)
644
{
645
ha_rollback_trans(session, all);
646
error= 1;
647
goto end;
648
}
649
}
650
error=ha_commit_one_phase(session, all) ? (cookie ? 2 : 1) : 0;
651
end:
652
if (is_real_trans)
653
start_waiting_global_read_lock(session);
654
}
655
return error;
656
}
657
658
/**
659
@note
660
This function does not care about global read lock. A caller should.
661
*/
662
int ha_commit_one_phase(Session *session, bool all)
663
{
664
int error=0;
665
Session_TRANS *trans=all ? &session->transaction.all : &session->transaction.stmt;
666
bool is_real_trans=all || session->transaction.all.ha_list == 0;
667
Ha_trx_info *ha_info= trans->ha_list, *ha_info_next;
668
if (ha_info)
669
{
670
for (; ha_info; ha_info= ha_info_next)
671
{
672
int err;
673
plugin::StorageEngine *engine= ha_info->engine();
674
if ((err= engine->commit(session, all)))
675
{
676
my_error(ER_ERROR_DURING_COMMIT, MYF(0), err);
677
error=1;
678
}
679
status_var_increment(session->status_var.ha_commit_count);
680
ha_info_next= ha_info->next();
681
ha_info->reset(); /* keep it conveniently zero-filled */
682
}
683
trans->ha_list= 0;
684
trans->no_2pc=0;
685
if (is_real_trans)
686
session->transaction.xid_state.xid.null();
687
if (all)
688
{
689
session->variables.tx_isolation=session->session_tx_isolation;
690
session->transaction.cleanup();
691
}
692
}
693
if (error == 0)
694
{
695
if (is_real_trans)
696
{
697
/*
698
* We commit the normal transaction by finalizing the transaction message
699
* and propogating the message to all registered replicators.
700
*/
701
ReplicationServices &replication_services= ReplicationServices::singleton();
702
replication_services.commitNormalTransaction(session);
703
}
704
}
705
return error;
706
}
707
708
709
int ha_rollback_trans(Session *session, bool all)
710
{
711
int error=0;
712
Session_TRANS *trans=all ? &session->transaction.all : &session->transaction.stmt;
713
Ha_trx_info *ha_info= trans->ha_list, *ha_info_next;
714
bool is_real_trans=all || session->transaction.all.ha_list == 0;
715
716
/*
717
We must not rollback the normal transaction if a statement
718
transaction is pending.
719
*/
720
assert(session->transaction.stmt.ha_list == NULL ||
721
trans == &session->transaction.stmt);
722
723
if (ha_info)
724
{
725
for (; ha_info; ha_info= ha_info_next)
726
{
727
int err;
728
plugin::StorageEngine *engine= ha_info->engine();
729
if ((err= engine->rollback(session, all)))
730
{ // cannot happen
731
my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), err);
732
error=1;
733
}
734
status_var_increment(session->status_var.ha_rollback_count);
735
ha_info_next= ha_info->next();
736
ha_info->reset(); /* keep it conveniently zero-filled */
737
}
738
trans->ha_list= 0;
739
trans->no_2pc=0;
740
if (is_real_trans)
741
session->transaction.xid_state.xid.null();
742
if (all)
743
{
744
session->variables.tx_isolation=session->session_tx_isolation;
745
session->transaction.cleanup();
746
}
747
}
748
if (all)
749
session->transaction_rollback_request= false;
750
751
/*
752
If a non-transactional table was updated, warn; don't warn if this is a
753
slave thread (because when a slave thread executes a ROLLBACK, it has
754
been read from the binary log, so it's 100% sure and normal to produce
755
error ER_WARNING_NOT_COMPLETE_ROLLBACK. If we sent the warning to the
756
slave SQL thread, it would not stop the thread but just be printed in
757
the error log; but we don't want users to wonder why they have this
758
message in the error log, so we don't send it.
759
*/
760
if (is_real_trans && session->transaction.all.modified_non_trans_table && session->killed != Session::KILL_CONNECTION)
761
push_warning(session, DRIZZLE_ERROR::WARN_LEVEL_WARN,
762
ER_WARNING_NOT_COMPLETE_ROLLBACK,
763
ER(ER_WARNING_NOT_COMPLETE_ROLLBACK));
764
return error;
765
}
766
767
/**
768
This is used to commit or rollback a single statement depending on
769
the value of error.
770
771
@note
772
Note that if the autocommit is on, then the following call inside
773
InnoDB will commit or rollback the whole transaction (= the statement). The
774
autocommit mechanism built into InnoDB is based on counting locks, but if
775
the user has used LOCK TABLES then that mechanism does not know to do the
776
commit.
777
*/
778
int ha_autocommit_or_rollback(Session *session, int error)
779
{
780
if (session->transaction.stmt.ha_list)
781
{
782
if (!error)
783
{
784
if (ha_commit_trans(session, 0))
785
error= 1;
786
}
787
else
788
{
789
(void) ha_rollback_trans(session, 0);
790
if (session->transaction_rollback_request)
791
(void) ha_rollback(session);
792
}
793
794
session->variables.tx_isolation=session->session_tx_isolation;
795
}
796
797
return error;
798
}
799
800
/**
801
return the list of XID's to a client, the same way SHOW commands do.
802
803
@note
804
I didn't find in XA specs that an RM cannot return the same XID twice,
805
so mysql_xa_recover does not filter XID's to ensure uniqueness.
806
It can be easily fixed later, if necessary.
807
*/
808
bool mysql_xa_recover(Session *session)
809
{
810
List<Item> field_list;
811
int i= 0;
812
XID_STATE *xs;
813
814
field_list.push_back(new Item_int("formatID", 0, MY_INT32_NUM_DECIMAL_DIGITS));
815
field_list.push_back(new Item_int("gtrid_length", 0, MY_INT32_NUM_DECIMAL_DIGITS));
816
field_list.push_back(new Item_int("bqual_length", 0, MY_INT32_NUM_DECIMAL_DIGITS));
817
field_list.push_back(new Item_empty_string("data",XIDDATASIZE));
818
819
if (session->client->sendFields(&field_list))
820
return 1;
821
822
pthread_mutex_lock(&LOCK_xid_cache);
823
while ((xs= (XID_STATE*)hash_element(&xid_cache, i++)))
824
{
825
if (xs->xa_state==XA_PREPARED)
826
{
827
session->client->store((int64_t)xs->xid.formatID);
828
session->client->store((int64_t)xs->xid.gtrid_length);
829
session->client->store((int64_t)xs->xid.bqual_length);
830
session->client->store(xs->xid.data,
831
xs->xid.gtrid_length+xs->xid.bqual_length);
832
if (session->client->flush())
833
{
834
pthread_mutex_unlock(&LOCK_xid_cache);
835
return 1;
836
}
837
}
838
}
839
840
pthread_mutex_unlock(&LOCK_xid_cache);
841
session->my_eof();
842
return 0;
843
}
844
845
846
int ha_rollback_to_savepoint(Session *session, SAVEPOINT *sv)
847
{
848
int error= 0;
849
Session_TRANS *trans= &session->transaction.all;
850
Ha_trx_info *ha_info, *ha_info_next;
851
852
trans->no_2pc=0;
853
/*
854
rolling back to savepoint in all storage engines that were part of the
855
transaction when the savepoint was set
856
*/
857
for (ha_info= sv->ha_list; ha_info; ha_info= ha_info->next())
858
{
859
int err;
860
plugin::StorageEngine *engine= ha_info->engine();
861
assert(engine);
862
if ((err= engine->savepoint_rollback(session,
863
(void *)(sv+1))))
864
{ // cannot happen
865
my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), err);
866
error= 1;
867
}
868
status_var_increment(session->status_var.ha_savepoint_rollback_count);
869
trans->no_2pc|= not engine->has_2pc();
870
}
871
/*
872
rolling back the transaction in all storage engines that were not part of
873
the transaction when the savepoint was set
874
*/
875
for (ha_info= trans->ha_list; ha_info != sv->ha_list;
876
ha_info= ha_info_next)
877
{
878
int err;
879
plugin::StorageEngine *engine= ha_info->engine();
880
if ((err= engine->rollback(session, !(0))))
881
{ // cannot happen
882
my_error(ER_ERROR_DURING_ROLLBACK, MYF(0), err);
883
error= 1;
884
}
885
status_var_increment(session->status_var.ha_rollback_count);
886
ha_info_next= ha_info->next();
887
ha_info->reset(); /* keep it conveniently zero-filled */
888
}
889
trans->ha_list= sv->ha_list;
890
return error;
891
}
892
893
/**
894
@note
895
according to the sql standard (ISO/IEC 9075-2:2003)
896
section "4.33.4 SQL-statements and transaction states",
897
SAVEPOINT is *not* transaction-initiating SQL-statement
898
*/
899
int ha_savepoint(Session *session, SAVEPOINT *sv)
900
{
901
int error= 0;
902
Session_TRANS *trans= &session->transaction.all;
903
Ha_trx_info *ha_info= trans->ha_list;
904
for (; ha_info; ha_info= ha_info->next())
905
{
906
int err;
907
plugin::StorageEngine *engine= ha_info->engine();
908
assert(engine);
909
#ifdef NOT_IMPLEMENTED /*- TODO (examine this againt the original code base) */
910
if (! engine->savepoint_set)
911
{
912
my_error(ER_CHECK_NOT_IMPLEMENTED, MYF(0), "SAVEPOINT");
913
error= 1;
914
break;
915
}
916
#endif
917
if ((err= engine->savepoint_set(session, (void *)(sv+1))))
918
{ // cannot happen
919
my_error(ER_GET_ERRNO, MYF(0), err);
920
error= 1;
921
}
922
status_var_increment(session->status_var.ha_savepoint_count);
923
}
924
/*
925
Remember the list of registered storage engines. All new
926
engines are prepended to the beginning of the list.
927
*/
928
sv->ha_list= trans->ha_list;
929
return error;
930
}
931
932
int ha_release_savepoint(Session *session, SAVEPOINT *sv)
933
{
934
int error= 0;
935
Ha_trx_info *ha_info= sv->ha_list;
936
937
for (; ha_info; ha_info= ha_info->next())
938
{
939
int err;
940
plugin::StorageEngine *engine= ha_info->engine();
941
/* Savepoint life time is enclosed into transaction life time. */
942
assert(engine);
943
if ((err= engine->savepoint_release(session,
944
(void *)(sv+1))))
945
{ // cannot happen
946
my_error(ER_GET_ERRNO, MYF(0), err);
947
error= 1;
948
}
949
}
950
return error;
951
}
Loggerhead is a web-based interface for Breezy
Version: 2.0.1