~drizzle-trunk/drizzle/development

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
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
 *
 *  Copyright (C) 2008 Sun Microsystems, Inc.
 *  Copyright (C) 2009-2010 Jay Pipes <jaypipes@gmail.com>
 *
 *  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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <config.h>

#include <drizzled/plugin/transactional_storage_engine.h>
#include <drizzled/resource_context.h>
#include <drizzled/session.h>

#include <vector>
#include <algorithm>
#include <functional>

namespace drizzled
{

namespace plugin
{

static std::vector<TransactionalStorageEngine *> vector_of_transactional_engines;

TransactionalStorageEngine::TransactionalStorageEngine(const std::string name_arg,
                                                       const std::bitset<HTON_BIT_SIZE> &flags_arg)
    : StorageEngine(name_arg, flags_arg)
{
}

TransactionalStorageEngine::~TransactionalStorageEngine()
{
}

void TransactionalStorageEngine::setTransactionReadWrite(Session& session)
{
  ResourceContext& resource_context= session.getResourceContext(*this);

  /*
    When a storage engine method is called, the transaction must
    have been started, unless it's a DDL call, for which the
    storage engine starts the transaction internally, and commits
    it internally, without registering in the ha_list.
    Unfortunately here we can't know know for sure if the engine
    has registered the transaction or not, so we must check.
  */
  if (resource_context.isStarted())
    resource_context.markModifiedData();
}

/**
  @details
  This function should be called when MySQL sends rows of a SELECT result set
  or the EOF mark to the client. It releases a possible adaptive hash index
  S-latch held by session in InnoDB and also releases a possible InnoDB query
  FIFO ticket to enter InnoDB. To save CPU time, InnoDB allows a session to
  keep them over several calls of the InnoDB Cursor interface when a join
  is executed. But when we let the control to pass to the client they have
  to be released because if the application program uses use_result(),
  it may deadlock on the S-latch if the application on another connection
  performs another SQL query. In MySQL-4.1 this is even more important because
  there a connection can have several SELECT queries open at the same time.

  @param session           the thread handle of the current connection

  @return
    always 0
*/
int TransactionalStorageEngine::releaseTemporaryLatches(Session *session)
{
  std::for_each(vector_of_transactional_engines.begin(), vector_of_transactional_engines.end(),
                std::bind2nd(std::mem_fun(&TransactionalStorageEngine::doReleaseTemporaryLatches),session));
  return 0;
}

struct StartTransactionFunc :public std::unary_function<TransactionalStorageEngine *, int>
{
  Session *session;
  start_transaction_option_t options;
  StartTransactionFunc(Session *in_session, start_transaction_option_t in_options) :
    session(in_session),
    options(in_options)
  {}
  result_type operator()(argument_type engine) const
  {
    return engine->startTransaction(session, options);
  }
};

int TransactionalStorageEngine::notifyStartTransaction(Session *session, start_transaction_option_t options)
{
  if (vector_of_transactional_engines.empty())
  {
    return 0;
  }
  else
  {
    StartTransactionFunc functor(session, options);
    std::vector<int> results;
    results.reserve(vector_of_transactional_engines.size());
    transform(vector_of_transactional_engines.begin(),
              vector_of_transactional_engines.end(),
              results.begin(),
              functor);
    return *std::max_element(results.begin(), results.end());
  }
}

bool TransactionalStorageEngine::addPlugin(TransactionalStorageEngine *engine)
{
  vector_of_transactional_engines.push_back(engine);

  return StorageEngine::addPlugin(engine);
}

void TransactionalStorageEngine::removePlugin(TransactionalStorageEngine *)
{
  vector_of_transactional_engines.clear();
}

} /* namespace plugin */
} /* namespace drizzled */