1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
/* Copyright (C) 2007 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; version 2 of the License.
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 */
#include "maria_def.h"
#include "trnman.h"
/**
@brief writes a COMMIT record to log and commits transaction in memory
@param trn transaction
@return Operation status
@retval 0 ok
@retval 1 error (disk error or out of memory)
*/
int ma_commit(TRN *trn)
{
if (trn->undo_lsn == 0) /* no work done, rollback (cheaper than commit) */
return trnman_rollback_trn(trn);
/*
- if COMMIT record is written before trnman_commit_trn():
if Checkpoint comes in the middle it will see trn is not committed,
then if crash, Recovery might roll back trn (if min(rec_lsn) is after
COMMIT record) and this is not an issue as
* transaction's updates were not made visible to other transactions
* "commit ok" was not sent to client
Alternatively, Recovery might commit trn (if min(rec_lsn) is before COMMIT
record), which is ok too. All in all it means that "trn committed" is not
100% equal to "COMMIT record written".
- if COMMIT record is written after trnman_commit_trn():
if crash happens between the two, trn will be rolled back which is an
issue (transaction's updates were made visible to other transactions).
So we need to go the first way.
*/
/**
@todo RECOVERY share's state is written to disk only in
maria_lock_database(), so COMMIT record is not the last record of the
transaction! It is probably an issue. Recovery of the state is a problem
not yet solved.
*/
LSN commit_lsn;
LEX_STRING log_array[TRANSLOG_INTERNAL_PARTS];
/*
We do not store "thd->transaction.xid_state.xid" for now, it will be
needed only when we support XA.
*/
return
translog_write_record(&commit_lsn, LOGREC_COMMIT,
trn, NULL, 0,
sizeof(log_array)/sizeof(log_array[0]),
log_array, NULL) ||
translog_flush(commit_lsn) || trnman_commit_trn(trn);
/*
Note: if trnman_commit_trn() fails above, we have already
written the COMMIT record, so Checkpoint and Recovery will see the
transaction as committed.
*/
}
|
