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|
/*****************************************************************************
Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2015, 2019, MariaDB Corporation.
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 Street, Fifth Floor, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file trx/trx0trx.cc
The transaction
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "trx0trx.h"
#ifdef WITH_WSREP
#include <mysql/service_wsrep.h>
#endif
#include <mysql/service_thd_error_context.h>
#include "btr0sea.h"
#include "lock0lock.h"
#include "log0log.h"
#include "os0proc.h"
#include "que0que.h"
#include "srv0mon.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "trx0purge.h"
#include "trx0rec.h"
#include "trx0roll.h"
#include "trx0rseg.h"
#include "trx0undo.h"
#include "trx0xa.h"
#include "ut0pool.h"
#include "ut0vec.h"
#include <set>
#include <new>
/** The bit pattern corresponding to TRX_ID_MAX */
const byte trx_id_max_bytes[8] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
};
/** The bit pattern corresponding to max timestamp */
const byte timestamp_max_bytes[7] = {
0x7f, 0xff, 0xff, 0xff, 0x0f, 0x42, 0x3f
};
static const ulint MAX_DETAILED_ERROR_LEN = 256;
/** Set of table_id */
typedef std::set<
table_id_t,
std::less<table_id_t>,
ut_allocator<table_id_t> > table_id_set;
/*************************************************************//**
Set detailed error message for the transaction. */
void
trx_set_detailed_error(
/*===================*/
trx_t* trx, /*!< in: transaction struct */
const char* msg) /*!< in: detailed error message */
{
ut_strlcpy(trx->detailed_error, msg, MAX_DETAILED_ERROR_LEN);
}
/*************************************************************//**
Set detailed error message for the transaction from a file. Note that the
file is rewinded before reading from it. */
void
trx_set_detailed_error_from_file(
/*=============================*/
trx_t* trx, /*!< in: transaction struct */
FILE* file) /*!< in: file to read message from */
{
os_file_read_string(file, trx->detailed_error, MAX_DETAILED_ERROR_LEN);
}
/********************************************************************//**
Initialize transaction object.
@param trx trx to initialize */
static
void
trx_init(
/*=====*/
trx_t* trx)
{
trx->no = TRX_ID_MAX;
trx->state = TRX_STATE_NOT_STARTED;
trx->is_recovered = false;
trx->op_info = "";
trx->active_commit_ordered = 0;
trx->isolation_level = TRX_ISO_REPEATABLE_READ;
trx->check_foreigns = true;
trx->check_unique_secondary = true;
trx->lock.n_rec_locks = 0;
trx->dict_operation = TRX_DICT_OP_NONE;
trx->table_id = 0;
trx->error_state = DB_SUCCESS;
trx->error_key_num = ULINT_UNDEFINED;
trx->undo_no = 0;
trx->rsegs.m_redo.rseg = NULL;
trx->rsegs.m_noredo.rseg = NULL;
trx->read_only = false;
trx->auto_commit = false;
trx->will_lock = 0;
trx->ddl = false;
trx->internal = false;
ut_d(trx->start_file = 0);
ut_d(trx->start_line = 0);
trx->magic_n = TRX_MAGIC_N;
trx->lock.que_state = TRX_QUE_RUNNING;
trx->last_sql_stat_start.least_undo_no = 0;
ut_ad(!trx->read_view.is_open());
trx->lock.rec_cached = 0;
trx->lock.table_cached = 0;
ut_ad(trx->get_flush_observer() == NULL);
}
/** For managing the life-cycle of the trx_t instance that we get
from the pool. */
struct TrxFactory {
/** Initializes a transaction object. It must be explicitly started
with trx_start_if_not_started() before using it. The default isolation
level is TRX_ISO_REPEATABLE_READ.
@param trx Transaction instance to initialise */
static void init(trx_t* trx)
{
/* Explicitly call the constructor of the already
allocated object. trx_t objects are allocated by
ut_zalloc_nokey() in Pool::Pool() which would not call
the constructors of the trx_t members. */
new(&trx->mod_tables) trx_mod_tables_t();
new(&trx->lock.table_locks) lock_list();
new(&trx->read_view) ReadView();
trx->rw_trx_hash_pins = 0;
trx_init(trx);
trx->dict_operation_lock_mode = 0;
trx->xid = UT_NEW_NOKEY(xid_t());
trx->detailed_error = reinterpret_cast<char*>(
ut_zalloc_nokey(MAX_DETAILED_ERROR_LEN));
trx->lock.lock_heap = mem_heap_create_typed(
1024, MEM_HEAP_FOR_LOCK_HEAP);
lock_trx_lock_list_init(&trx->lock.trx_locks);
UT_LIST_INIT(trx->lock.evicted_tables,
&dict_table_t::table_LRU);
UT_LIST_INIT(
trx->trx_savepoints,
&trx_named_savept_t::trx_savepoints);
mutex_create(LATCH_ID_TRX, &trx->mutex);
}
/** Release resources held by the transaction object.
@param trx the transaction for which to release resources */
static void destroy(trx_t* trx)
{
ut_a(trx->magic_n == TRX_MAGIC_N);
ut_ad(!trx->mysql_thd);
ut_a(trx->lock.wait_lock == NULL);
ut_a(trx->lock.wait_thr == NULL);
ut_a(trx->dict_operation_lock_mode == 0);
if (trx->lock.lock_heap != NULL) {
mem_heap_free(trx->lock.lock_heap);
trx->lock.lock_heap = NULL;
}
ut_a(UT_LIST_GET_LEN(trx->lock.trx_locks) == 0);
ut_ad(UT_LIST_GET_LEN(trx->lock.evicted_tables) == 0);
UT_DELETE(trx->xid);
ut_free(trx->detailed_error);
mutex_free(&trx->mutex);
trx->mod_tables.~trx_mod_tables_t();
ut_ad(!trx->read_view.is_open());
trx->lock.table_locks.~lock_list();
trx->read_view.~ReadView();
}
/** Enforce any invariants here, this is called before the transaction
is added to the pool.
@return true if all OK */
static bool debug(const trx_t* trx)
{
ut_a(trx->error_state == DB_SUCCESS);
ut_a(trx->magic_n == TRX_MAGIC_N);
ut_ad(!trx->read_only);
ut_ad(trx->state == TRX_STATE_NOT_STARTED);
ut_ad(trx->dict_operation == TRX_DICT_OP_NONE);
ut_ad(trx->mysql_thd == 0);
ut_a(trx->lock.wait_thr == NULL);
ut_a(trx->lock.wait_lock == NULL);
ut_a(trx->dict_operation_lock_mode == 0);
ut_a(UT_LIST_GET_LEN(trx->lock.trx_locks) == 0);
ut_ad(trx->autoinc_locks == NULL);
ut_ad(trx->lock.table_locks.empty());
return(true);
}
};
/** The lock strategy for TrxPool */
struct TrxPoolLock {
TrxPoolLock() { }
/** Create the mutex */
void create()
{
mutex_create(LATCH_ID_TRX_POOL, &m_mutex);
}
/** Acquire the mutex */
void enter() { mutex_enter(&m_mutex); }
/** Release the mutex */
void exit() { mutex_exit(&m_mutex); }
/** Free the mutex */
void destroy() { mutex_free(&m_mutex); }
/** Mutex to use */
ib_mutex_t m_mutex;
};
/** The lock strategy for the TrxPoolManager */
struct TrxPoolManagerLock {
TrxPoolManagerLock() { }
/** Create the mutex */
void create()
{
mutex_create(LATCH_ID_TRX_POOL_MANAGER, &m_mutex);
}
/** Acquire the mutex */
void enter() { mutex_enter(&m_mutex); }
/** Release the mutex */
void exit() { mutex_exit(&m_mutex); }
/** Free the mutex */
void destroy() { mutex_free(&m_mutex); }
/** Mutex to use */
ib_mutex_t m_mutex;
};
/** Use explicit mutexes for the trx_t pool and its manager. */
typedef Pool<trx_t, TrxFactory, TrxPoolLock> trx_pool_t;
typedef PoolManager<trx_pool_t, TrxPoolManagerLock > trx_pools_t;
/** The trx_t pool manager */
static trx_pools_t* trx_pools;
/** Size of on trx_t pool in bytes. */
static const ulint MAX_TRX_BLOCK_SIZE = 1024 * 1024 * 4;
/** Create the trx_t pool */
void
trx_pool_init()
{
trx_pools = UT_NEW_NOKEY(trx_pools_t(MAX_TRX_BLOCK_SIZE));
ut_a(trx_pools != 0);
}
/** Destroy the trx_t pool */
void
trx_pool_close()
{
UT_DELETE(trx_pools);
trx_pools = 0;
}
/** @return a trx_t instance from trx_pools. */
trx_t *trx_create()
{
trx_t* trx = trx_pools->get();
assert_trx_is_free(trx);
mem_heap_t* heap;
ib_alloc_t* alloc;
/* We just got trx from pool, it should be non locking */
ut_ad(trx->will_lock == 0);
ut_ad(trx->state == TRX_STATE_NOT_STARTED);
ut_ad(!trx->rw_trx_hash_pins);
DBUG_LOG("trx", "Create: " << trx);
heap = mem_heap_create(sizeof(ib_vector_t) + sizeof(void*) * 8);
alloc = ib_heap_allocator_create(heap);
/* Remember to free the vector explicitly in trx_free(). */
trx->autoinc_locks = ib_vector_create(alloc, sizeof(void**), 4);
/* Should have been either just initialized or .clear()ed by
trx_free(). */
ut_ad(trx->mod_tables.empty());
ut_ad(trx->lock.table_locks.empty());
ut_ad(UT_LIST_GET_LEN(trx->lock.trx_locks) == 0);
ut_ad(trx->lock.n_rec_locks == 0);
ut_ad(trx->lock.table_cached == 0);
ut_ad(trx->lock.rec_cached == 0);
ut_ad(UT_LIST_GET_LEN(trx->lock.evicted_tables) == 0);
#ifdef WITH_WSREP
trx->wsrep_event = NULL;
#endif /* WITH_WSREP */
trx_sys.register_trx(trx);
return(trx);
}
/**
Release a trx_t instance back to the pool.
@param trx the instance to release.
*/
void trx_free(trx_t*& trx)
{
ut_ad(!trx->declared_to_be_inside_innodb);
ut_ad(!trx->n_mysql_tables_in_use);
ut_ad(!trx->mysql_n_tables_locked);
ut_ad(!trx->internal);
if (trx->declared_to_be_inside_innodb) {
ib::error() << "Freeing a trx (" << trx << ", "
<< trx_get_id_for_print(trx) << ") which is declared"
" to be processing inside InnoDB";
trx_print(stderr, trx, 600);
putc('\n', stderr);
/* This is an error but not a fatal error. We must keep
the counters like srv_conc.n_active accurate. */
srv_conc_force_exit_innodb(trx);
}
if (trx->n_mysql_tables_in_use != 0
|| trx->mysql_n_tables_locked != 0) {
ib::error() << "MySQL is freeing a thd though"
" trx->n_mysql_tables_in_use is "
<< trx->n_mysql_tables_in_use
<< " and trx->mysql_n_tables_locked is "
<< trx->mysql_n_tables_locked << ".";
trx_print(stderr, trx, 600);
ut_print_buf(stderr, trx, sizeof(trx_t));
putc('\n', stderr);
}
trx->dict_operation = TRX_DICT_OP_NONE;
assert_trx_is_inactive(trx);
trx_sys.deregister_trx(trx);
assert_trx_is_free(trx);
trx_sys.rw_trx_hash.put_pins(trx);
trx->mysql_thd = 0;
trx->mysql_log_file_name = 0;
// FIXME: We need to avoid this heap free/alloc for each commit.
if (trx->autoinc_locks != NULL) {
ut_ad(ib_vector_is_empty(trx->autoinc_locks));
/* We allocated a dedicated heap for the vector. */
ib_vector_free(trx->autoinc_locks);
trx->autoinc_locks = NULL;
}
trx->mod_tables.clear();
/* trx locking state should have been reset before returning trx
to pool */
ut_ad(trx->will_lock == 0);
trx_pools->mem_free(trx);
/* Unpoison the memory for innodb_monitor_set_option;
it is operating also on the freed transaction objects. */
MEM_UNDEFINED(&trx->mutex, sizeof trx->mutex);
/* Declare the contents as initialized for Valgrind;
we checked that it was initialized in trx_pools->mem_free(trx). */
UNIV_MEM_VALID(&trx->mutex, sizeof trx->mutex);
trx = NULL;
}
/** Transition to committed state, to release implicit locks. */
inline void trx_t::commit_state()
{
ut_ad(state == TRX_STATE_PREPARED
|| state == TRX_STATE_PREPARED_RECOVERED
|| state == TRX_STATE_ACTIVE);
/* This makes the transaction committed in memory and makes its
changes to data visible to other transactions. NOTE that there is a
small discrepancy from the strict formal visibility rules here: a
user of the database can see modifications made by another
transaction T even before the necessary redo log segment has been
flushed to the disk. If the database happens to crash before the
flush, the user has seen modifications from T which will never be a
committed transaction. However, any transaction T2 which sees the
modifications of the committing transaction T, and which also itself
makes modifications to the database, will get an lsn larger than the
committing transaction T. In the case where the log flush fails, and
T never gets committed, also T2 will never get committed. */
trx_mutex_enter(this);
state= TRX_STATE_COMMITTED_IN_MEMORY;
trx_mutex_exit(this);
ut_ad(id || !is_referenced());
}
/** Release any explicit locks of a committing transaction. */
inline void trx_t::release_locks()
{
DBUG_ASSERT(state == TRX_STATE_COMMITTED_IN_MEMORY);
DBUG_ASSERT(!is_referenced());
if (UT_LIST_GET_LEN(lock.trx_locks))
{
lock_release(this);
lock.n_rec_locks = 0;
ut_ad(UT_LIST_GET_LEN(lock.trx_locks) == 0);
ut_ad(ib_vector_is_empty(autoinc_locks));
mem_heap_empty(lock.lock_heap);
}
lock.table_locks.clear(); /* outside "if" to work around MDEV-20483 */
}
/** At shutdown, frees a transaction object. */
void
trx_free_at_shutdown(trx_t *trx)
{
ut_ad(trx->is_recovered);
ut_a(trx_state_eq(trx, TRX_STATE_PREPARED)
|| trx_state_eq(trx, TRX_STATE_PREPARED_RECOVERED)
|| (trx_state_eq(trx, TRX_STATE_ACTIVE)
&& (!srv_was_started
|| srv_operation == SRV_OPERATION_RESTORE
|| srv_operation == SRV_OPERATION_RESTORE_EXPORT
|| srv_read_only_mode
|| srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO
|| (!srv_is_being_started
&& !srv_undo_sources && srv_fast_shutdown))));
ut_a(trx->magic_n == TRX_MAGIC_N);
trx->commit_state();
trx->release_locks();
trx_undo_free_at_shutdown(trx);
ut_a(!trx->read_only);
DBUG_LOG("trx", "Free prepared: " << trx);
trx->state = TRX_STATE_NOT_STARTED;
ut_ad(!UT_LIST_GET_LEN(trx->lock.trx_locks));
trx->id = 0;
trx_free(trx);
}
/**
Disconnect a prepared transaction from MySQL
@param[in,out] trx transaction
*/
void trx_disconnect_prepared(trx_t *trx)
{
ut_ad(trx_state_eq(trx, TRX_STATE_PREPARED));
ut_ad(trx->mysql_thd);
trx->read_view.close();
trx->is_recovered= true;
trx->mysql_thd= NULL;
/* todo/fixme: suggest to do it at innodb prepare */
trx->will_lock= 0;
}
/****************************************************************//**
Resurrect the table locks for a resurrected transaction. */
static
void
trx_resurrect_table_locks(
/*======================*/
trx_t* trx, /*!< in/out: transaction */
const trx_undo_t* undo) /*!< in: undo log */
{
mtr_t mtr;
page_t* undo_page;
trx_undo_rec_t* undo_rec;
table_id_set tables;
ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE) ||
trx_state_eq(trx, TRX_STATE_PREPARED));
ut_ad(undo->rseg == trx->rsegs.m_redo.rseg);
if (undo->empty()) {
return;
}
mtr_start(&mtr);
/* trx_rseg_mem_create() may have acquired an X-latch on this
page, so we cannot acquire an S-latch. */
undo_page = trx_undo_page_get(
page_id_t(trx->rsegs.m_redo.rseg->space->id,
undo->top_page_no), &mtr);
undo_rec = undo_page + undo->top_offset;
do {
ulint type;
undo_no_t undo_no;
table_id_t table_id;
ulint cmpl_info;
bool updated_extern;
page_t* undo_rec_page = page_align(undo_rec);
if (undo_rec_page != undo_page) {
mtr.release_page(undo_page, MTR_MEMO_PAGE_X_FIX);
undo_page = undo_rec_page;
}
trx_undo_rec_get_pars(
undo_rec, &type, &cmpl_info,
&updated_extern, &undo_no, &table_id);
tables.insert(table_id);
undo_rec = trx_undo_get_prev_rec(
undo_rec, undo->hdr_page_no,
undo->hdr_offset, false, &mtr);
} while (undo_rec);
mtr_commit(&mtr);
for (table_id_set::const_iterator i = tables.begin();
i != tables.end(); i++) {
if (dict_table_t* table = dict_table_open_on_id(
*i, FALSE, DICT_TABLE_OP_LOAD_TABLESPACE)) {
if (!table->is_readable()) {
mutex_enter(&dict_sys.mutex);
dict_table_close(table, TRUE, FALSE);
dict_sys.remove(table);
mutex_exit(&dict_sys.mutex);
continue;
}
if (trx->state == TRX_STATE_PREPARED) {
trx->mod_tables.insert(
trx_mod_tables_t::value_type(table,
0));
}
lock_table_ix_resurrect(table, trx);
DBUG_LOG("ib_trx",
"resurrect " << ib::hex(trx->id)
<< " IX lock on " << table->name);
dict_table_close(table, FALSE, FALSE);
}
}
}
/**
Resurrect the transactions that were doing inserts/updates the time of the
crash, they need to be undone.
*/
static void trx_resurrect(trx_undo_t *undo, trx_rseg_t *rseg,
time_t start_time, ulonglong start_time_micro,
uint64_t *rows_to_undo,
bool is_old_insert)
{
trx_state_t state;
/*
This is single-threaded startup code, we do not need the
protection of trx->mutex or trx_sys.mutex here.
*/
switch (undo->state)
{
case TRX_UNDO_ACTIVE:
state= TRX_STATE_ACTIVE;
break;
case TRX_UNDO_PREPARED:
/*
Prepared transactions are left in the prepared state
waiting for a commit or abort decision from MySQL
*/
ib::info() << "Transaction " << undo->trx_id
<< " was in the XA prepared state.";
state= TRX_STATE_PREPARED;
break;
default:
if (is_old_insert && srv_force_recovery < SRV_FORCE_NO_TRX_UNDO)
trx_undo_commit_cleanup(undo, false);
return;
}
trx_t *trx= trx_create();
trx->state= state;
ut_d(trx->start_file= __FILE__);
ut_d(trx->start_line= __LINE__);
ut_ad(trx->no == TRX_ID_MAX);
if (is_old_insert)
trx->rsegs.m_redo.old_insert= undo;
else
trx->rsegs.m_redo.undo= undo;
trx->undo_no= undo->top_undo_no + 1;
trx->rsegs.m_redo.rseg= rseg;
/*
For transactions with active data will not have rseg size = 1
or will not qualify for purge limit criteria. So it is safe to increment
this trx_ref_count w/o mutex protection.
*/
++trx->rsegs.m_redo.rseg->trx_ref_count;
*trx->xid= undo->xid;
trx->id= undo->trx_id;
trx->is_recovered= true;
trx->start_time= start_time;
trx->start_time_micro= start_time_micro;
if (undo->dict_operation)
{
trx_set_dict_operation(trx, TRX_DICT_OP_TABLE);
if (!trx->table_id)
trx->table_id= undo->table_id;
}
trx_sys.rw_trx_hash.insert(trx);
trx_sys.rw_trx_hash.put_pins(trx);
trx_resurrect_table_locks(trx, undo);
if (trx_state_eq(trx, TRX_STATE_ACTIVE))
*rows_to_undo+= trx->undo_no;
}
/** Initialize (resurrect) transactions at startup. */
void
trx_lists_init_at_db_start()
{
ut_a(srv_is_being_started);
ut_ad(!srv_was_started);
if (srv_operation == SRV_OPERATION_RESTORE) {
/* mariabackup --prepare only deals with
the redo log and the data files, not with
transactions or the data dictionary. */
trx_rseg_array_init();
return;
}
if (srv_force_recovery >= SRV_FORCE_NO_UNDO_LOG_SCAN) {
return;
}
purge_sys.create();
trx_rseg_array_init();
/* Look from the rollback segments if there exist undo logs for
transactions. */
const time_t start_time = time(NULL);
const ulonglong start_time_micro= microsecond_interval_timer();
uint64_t rows_to_undo = 0;
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
trx_undo_t* undo;
trx_rseg_t* rseg = trx_sys.rseg_array[i];
/* Some rollback segment may be unavailable,
especially if the server was previously run with a
non-default value of innodb_undo_logs. */
if (rseg == NULL) {
continue;
}
/* Resurrect transactions that were doing inserts
using the old separate insert_undo log. */
undo = UT_LIST_GET_FIRST(rseg->old_insert_list);
while (undo) {
trx_undo_t* next = UT_LIST_GET_NEXT(undo_list, undo);
trx_resurrect(undo, rseg, start_time, start_time_micro,
&rows_to_undo, true);
undo = next;
}
/* Ressurrect other transactions. */
for (undo = UT_LIST_GET_FIRST(rseg->undo_list);
undo != NULL;
undo = UT_LIST_GET_NEXT(undo_list, undo)) {
trx_t *trx = trx_sys.find(0, undo->trx_id, false);
if (!trx) {
trx_resurrect(undo, rseg, start_time,
start_time_micro,
&rows_to_undo, false);
} else {
ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE) ||
trx_state_eq(trx, TRX_STATE_PREPARED));
ut_ad(trx->start_time == start_time);
ut_ad(trx->is_recovered);
ut_ad(trx->rsegs.m_redo.rseg == rseg);
ut_ad(trx->rsegs.m_redo.rseg->trx_ref_count);
trx->rsegs.m_redo.undo = undo;
if (undo->top_undo_no >= trx->undo_no) {
if (trx_state_eq(trx,
TRX_STATE_ACTIVE)) {
rows_to_undo -= trx->undo_no;
rows_to_undo +=
undo->top_undo_no + 1;
}
trx->undo_no = undo->top_undo_no + 1;
}
trx_resurrect_table_locks(trx, undo);
}
}
}
if (trx_sys.rw_trx_hash.size()) {
ib::info() << trx_sys.rw_trx_hash.size()
<< " transaction(s) which must be rolled back or"
" cleaned up in total " << rows_to_undo
<< " row operations to undo";
ib::info() << "Trx id counter is " << trx_sys.get_max_trx_id();
}
trx_sys.clone_oldest_view();
}
/** Assign a persistent rollback segment in a round-robin fashion,
evenly distributed between 0 and innodb_undo_logs-1
@return persistent rollback segment
@retval NULL if innodb_read_only */
static trx_rseg_t* trx_assign_rseg_low()
{
if (srv_read_only_mode) {
ut_ad(srv_undo_logs == ULONG_UNDEFINED);
return(NULL);
}
/* The first slot is always assigned to the system tablespace. */
ut_ad(trx_sys.rseg_array[0]->space == fil_system.sys_space);
/* Choose a rollback segment evenly distributed between 0 and
innodb_undo_logs-1 in a round-robin fashion, skipping those
undo tablespaces that are scheduled for truncation.
Because rseg_slot is not protected by atomics or any mutex, race
conditions are possible, meaning that multiple transactions
that start modifications concurrently will write their undo
log to the same rollback segment. */
static ulong rseg_slot;
ulint slot = rseg_slot++ % srv_undo_logs;
trx_rseg_t* rseg;
#ifdef UNIV_DEBUG
ulint start_scan_slot = slot;
bool look_for_rollover = false;
#endif /* UNIV_DEBUG */
bool allocated = false;
do {
for (;;) {
rseg = trx_sys.rseg_array[slot];
#ifdef UNIV_DEBUG
/* Ensure that we are not revisiting the same
slot that we have already inspected. */
if (look_for_rollover) {
ut_ad(start_scan_slot != slot);
}
look_for_rollover = true;
#endif /* UNIV_DEBUG */
slot = (slot + 1) % srv_undo_logs;
if (rseg == NULL) {
continue;
}
ut_ad(rseg->is_persistent());
if (rseg->space != fil_system.sys_space) {
if (rseg->skip_allocation
|| !srv_undo_tablespaces) {
continue;
}
} else if (trx_rseg_t* next
= trx_sys.rseg_array[slot]) {
if (next->space != fil_system.sys_space
&& srv_undo_tablespaces > 0) {
/** If dedicated
innodb_undo_tablespaces have
been configured, try to use them
instead of the system tablespace. */
continue;
}
}
break;
}
/* By now we have only selected the rseg but not marked it
allocated. By marking it allocated we are ensuring that it will
never be selected for UNDO truncate purge. */
mutex_enter(&rseg->mutex);
if (!rseg->skip_allocation) {
rseg->trx_ref_count++;
allocated = true;
}
mutex_exit(&rseg->mutex);
} while (!allocated);
ut_ad(rseg->trx_ref_count > 0);
ut_ad(rseg->is_persistent());
return(rseg);
}
/** Set the innodb_log_optimize_ddl page flush observer
@param[in,out] space tablespace
@param[in,out] stage performance_schema accounting */
void trx_t::set_flush_observer(fil_space_t* space, ut_stage_alter_t* stage)
{
flush_observer = UT_NEW_NOKEY(FlushObserver(space, this, stage));
}
/** Remove the flush observer */
void trx_t::remove_flush_observer()
{
UT_DELETE(flush_observer);
flush_observer = NULL;
}
/** Assign a rollback segment for modifying temporary tables.
@return the assigned rollback segment */
trx_rseg_t*
trx_t::assign_temp_rseg()
{
ut_ad(!rsegs.m_noredo.rseg);
ut_ad(!trx_is_autocommit_non_locking(this));
compile_time_assert(ut_is_2pow(TRX_SYS_N_RSEGS));
/* Choose a temporary rollback segment between 0 and 127
in a round-robin fashion. Because rseg_slot is not protected by
atomics or any mutex, race conditions are possible, meaning that
multiple transactions that start modifications concurrently
will write their undo log to the same rollback segment. */
static ulong rseg_slot;
trx_rseg_t* rseg = trx_sys.temp_rsegs[
rseg_slot++ & (TRX_SYS_N_RSEGS - 1)];
ut_ad(!rseg->is_persistent());
rsegs.m_noredo.rseg = rseg;
if (id == 0) {
trx_sys.register_rw(this);
}
ut_ad(!rseg->is_persistent());
return(rseg);
}
/****************************************************************//**
Starts a transaction. */
static
void
trx_start_low(
/*==========*/
trx_t* trx, /*!< in: transaction */
bool read_write) /*!< in: true if read-write transaction */
{
ut_ad(!trx->in_rollback);
ut_ad(!trx->is_recovered);
ut_ad(trx->start_line != 0);
ut_ad(trx->start_file != 0);
ut_ad(trx->roll_limit == 0);
ut_ad(trx->error_state == DB_SUCCESS);
ut_ad(trx->rsegs.m_redo.rseg == NULL);
ut_ad(trx->rsegs.m_noredo.rseg == NULL);
ut_ad(trx_state_eq(trx, TRX_STATE_NOT_STARTED));
ut_ad(UT_LIST_GET_LEN(trx->lock.trx_locks) == 0);
/* Check whether it is an AUTOCOMMIT SELECT */
trx->auto_commit = thd_trx_is_auto_commit(trx->mysql_thd);
trx->read_only = srv_read_only_mode
|| (!trx->ddl && !trx->internal
&& thd_trx_is_read_only(trx->mysql_thd));
if (!trx->auto_commit) {
++trx->will_lock;
} else if (trx->will_lock == 0) {
trx->read_only = true;
}
#ifdef WITH_WSREP
trx->xid->null();
#endif /* WITH_WSREP */
/* The initial value for trx->no: TRX_ID_MAX is used in
read_view_open_now: */
trx->no = TRX_ID_MAX;
ut_a(ib_vector_is_empty(trx->autoinc_locks));
ut_a(trx->lock.table_locks.empty());
/* No other thread can access this trx object through rw_trx_hash, thus
we don't need trx_sys.mutex protection for that purpose. Still this
trx can be found through trx_sys.trx_list, which means state
change must be protected by e.g. trx->mutex.
For now we update it without mutex protection, because original code
did it this way. It has to be reviewed and fixed properly. */
trx->state = TRX_STATE_ACTIVE;
/* By default all transactions are in the read-only list unless they
are non-locking auto-commit read only transactions or background
(internal) transactions. Note: Transactions marked explicitly as
read only can write to temporary tables, we put those on the RO
list too. */
if (!trx->read_only
&& (trx->mysql_thd == 0 || read_write || trx->ddl)) {
/* Temporary rseg is assigned only if the transaction
updates a temporary table */
trx->rsegs.m_redo.rseg = trx_assign_rseg_low();
ut_ad(trx->rsegs.m_redo.rseg != 0
|| srv_read_only_mode
|| srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO);
trx_sys.register_rw(trx);
} else {
if (!trx_is_autocommit_non_locking(trx)) {
/* If this is a read-only transaction that is writing
to a temporary table then it needs a transaction id
to write to the temporary table. */
if (read_write) {
ut_ad(!srv_read_only_mode);
trx_sys.register_rw(trx);
}
} else {
ut_ad(!read_write);
}
}
trx->start_time = time(NULL);
trx->start_time_micro = trx->mysql_thd
? thd_query_start_micro(trx->mysql_thd)
: microsecond_interval_timer();
ut_a(trx->error_state == DB_SUCCESS);
MONITOR_INC(MONITOR_TRX_ACTIVE);
}
/** Set the serialisation number for a persistent committed transaction.
@param[in,out] trx committed transaction with persistent changes */
static
void
trx_serialise(trx_t* trx)
{
trx_rseg_t *rseg = trx->rsegs.m_redo.rseg;
ut_ad(rseg);
ut_ad(mutex_own(&rseg->mutex));
if (rseg->last_page_no == FIL_NULL) {
mutex_enter(&purge_sys.pq_mutex);
}
trx_sys.assign_new_trx_no(trx);
/* If the rollback segment is not empty then the
new trx_t::no can't be less than any trx_t::no
already in the rollback segment. User threads only
produce events when a rollback segment is empty. */
if (rseg->last_page_no == FIL_NULL) {
purge_sys.purge_queue.push(TrxUndoRsegs(trx->no, *rseg));
mutex_exit(&purge_sys.pq_mutex);
}
}
/****************************************************************//**
Assign the transaction its history serialisation number and write the
update UNDO log record to the assigned rollback segment. */
static
void
trx_write_serialisation_history(
/*============================*/
trx_t* trx, /*!< in/out: transaction */
mtr_t* mtr) /*!< in/out: mini-transaction */
{
/* Change the undo log segment states from TRX_UNDO_ACTIVE to some
other state: these modifications to the file data structure define
the transaction as committed in the file based domain, at the
serialization point of the log sequence number lsn obtained below. */
/* We have to hold the rseg mutex because update log headers have
to be put to the history list in the (serialisation) order of the
UNDO trx number. This is required for the purge in-memory data
structures too. */
if (trx_undo_t* undo = trx->rsegs.m_noredo.undo) {
/* Undo log for temporary tables is discarded at transaction
commit. There is no purge for temporary tables, and also no
MVCC, because they are private to a session. */
mtr_t temp_mtr;
temp_mtr.start();
temp_mtr.set_log_mode(MTR_LOG_NO_REDO);
mutex_enter(&trx->rsegs.m_noredo.rseg->mutex);
trx_undo_set_state_at_finish(undo, &temp_mtr);
mutex_exit(&trx->rsegs.m_noredo.rseg->mutex);
temp_mtr.commit();
}
trx_rseg_t* rseg = trx->rsegs.m_redo.rseg;
if (!rseg) {
ut_ad(!trx->rsegs.m_redo.undo);
ut_ad(!trx->rsegs.m_redo.old_insert);
return;
}
trx_undo_t*& undo = trx->rsegs.m_redo.undo;
trx_undo_t*& old_insert = trx->rsegs.m_redo.old_insert;
if (!undo && !old_insert) {
return;
}
ut_ad(!trx->read_only);
ut_ad(!undo || undo->rseg == rseg);
ut_ad(!old_insert || old_insert->rseg == rseg);
mutex_enter(&rseg->mutex);
/* Assign the transaction serialisation number and add any
undo log to the purge queue. */
trx_serialise(trx);
if (UNIV_LIKELY_NULL(old_insert)) {
UT_LIST_REMOVE(rseg->old_insert_list, old_insert);
trx_purge_add_undo_to_history(trx, old_insert, mtr);
}
if (undo) {
UT_LIST_REMOVE(rseg->undo_list, undo);
trx_purge_add_undo_to_history(trx, undo, mtr);
}
mutex_exit(&rseg->mutex);
MONITOR_INC(MONITOR_TRX_COMMIT_UNDO);
trx->mysql_log_file_name = NULL;
}
/********************************************************************
Finalize a transaction containing updates for a FTS table. */
static
void
trx_finalize_for_fts_table(
/*=======================*/
fts_trx_table_t* ftt) /* in: FTS trx table */
{
fts_t* fts = ftt->table->fts;
fts_doc_ids_t* doc_ids = ftt->added_doc_ids;
mutex_enter(&fts->bg_threads_mutex);
if (fts->fts_status & BG_THREAD_STOP) {
/* The table is about to be dropped, no use
adding anything to its work queue. */
mutex_exit(&fts->bg_threads_mutex);
} else {
mem_heap_t* heap;
mutex_exit(&fts->bg_threads_mutex);
ut_a(fts->add_wq);
heap = static_cast<mem_heap_t*>(doc_ids->self_heap->arg);
ib_wqueue_add(fts->add_wq, doc_ids, heap);
/* fts_trx_table_t no longer owns the list. */
ftt->added_doc_ids = NULL;
}
}
/******************************************************************//**
Finalize a transaction containing updates to FTS tables. */
static
void
trx_finalize_for_fts(
/*=================*/
trx_t* trx, /*!< in/out: transaction */
bool is_commit) /*!< in: true if the transaction was
committed, false if it was rolled back. */
{
if (is_commit) {
const ib_rbt_node_t* node;
ib_rbt_t* tables;
fts_savepoint_t* savepoint;
savepoint = static_cast<fts_savepoint_t*>(
ib_vector_last(trx->fts_trx->savepoints));
tables = savepoint->tables;
for (node = rbt_first(tables);
node;
node = rbt_next(tables, node)) {
fts_trx_table_t** ftt;
ftt = rbt_value(fts_trx_table_t*, node);
if ((*ftt)->added_doc_ids) {
trx_finalize_for_fts_table(*ftt);
}
}
}
fts_trx_free(trx->fts_trx);
trx->fts_trx = NULL;
}
/**********************************************************************//**
If required, flushes the log to disk based on the value of
innodb_flush_log_at_trx_commit. */
static
void
trx_flush_log_if_needed_low(
/*========================*/
lsn_t lsn) /*!< in: lsn up to which logs are to be
flushed. */
{
bool flush = srv_file_flush_method != SRV_NOSYNC;
switch (srv_flush_log_at_trx_commit) {
case 3:
case 2:
/* Write the log but do not flush it to disk */
flush = false;
/* fall through */
case 1:
/* Write the log and optionally flush it to disk */
log_write_up_to(lsn, flush);
return;
case 0:
/* Do nothing */
return;
}
ut_error;
}
/**********************************************************************//**
If required, flushes the log to disk based on the value of
innodb_flush_log_at_trx_commit. */
static
void
trx_flush_log_if_needed(
/*====================*/
lsn_t lsn, /*!< in: lsn up to which logs are to be
flushed. */
trx_t* trx) /*!< in/out: transaction */
{
trx->op_info = "flushing log";
trx_flush_log_if_needed_low(lsn);
trx->op_info = "";
}
/**********************************************************************//**
For each table that has been modified by the given transaction: update
its dict_table_t::update_time with the current timestamp. Clear the list
of the modified tables at the end. */
static
void
trx_update_mod_tables_timestamp(
/*============================*/
trx_t* trx) /*!< in: transaction */
{
/* consider using trx->start_time if calling time() is too
expensive here */
const time_t now = time(NULL);
trx_mod_tables_t::const_iterator end = trx->mod_tables.end();
#ifdef UNIV_DEBUG
# if MYSQL_VERSION_ID >= 100405
# define dict_sys_mutex dict_sys.mutex
# else
# define dict_sys_mutex dict_sys->mutex
# endif
const bool preserve_tables = !innodb_evict_tables_on_commit_debug
|| trx->is_recovered /* avoid trouble with XA recovery */
# if 1 /* if dict_stats_exec_sql() were not playing dirty tricks */
|| mutex_own(&dict_sys_mutex)
# else /* this would be more proper way to do it */
|| trx->dict_operation_lock_mode || trx->dict_operation
# endif
;
#endif
for (trx_mod_tables_t::const_iterator it = trx->mod_tables.begin();
it != end;
++it) {
/* This could be executed by multiple threads concurrently
on the same table object. This is fine because time_t is
word size or less. And _purely_ _theoretically_, even if
time_t write is not atomic, likely the value of 'now' is
the same in all threads and even if it is not, getting a
"garbage" in table->update_time is justified because
protecting it with a latch here would be too performance
intrusive. */
dict_table_t* table = it->first;
table->update_time = now;
#ifdef UNIV_DEBUG
if (preserve_tables || table->get_ref_count()) {
/* do not evict when committing DDL operations
or if some other transaction is holding the
table handle */
continue;
}
/* recheck while holding the mutex that blocks
table->acquire() */
mutex_enter(&dict_sys_mutex);
if (!table->get_ref_count()) {
# if MYSQL_VERSION_ID >= 100405
dict_sys.remove(table, true);
# else
dict_table_remove_from_cache_low(table, true);
# endif
}
mutex_exit(&dict_sys_mutex);
#endif
}
trx->mod_tables.clear();
}
/** Evict a table definition due to the rollback of ALTER TABLE.
@param[in] table_id table identifier */
void trx_t::evict_table(table_id_t table_id)
{
ut_ad(in_rollback);
dict_table_t* table = dict_table_open_on_id(
table_id, true, DICT_TABLE_OP_OPEN_ONLY_IF_CACHED);
if (!table) {
return;
}
if (!table->release()) {
/* This must be a DDL operation that is being rolled
back in an active connection. */
ut_a(table->get_ref_count() == 1);
ut_ad(!is_recovered);
ut_ad(mysql_thd);
return;
}
/* This table should only be locked by this transaction, if at all. */
ut_ad(UT_LIST_GET_LEN(table->locks) <= 1);
const bool locked = UT_LIST_GET_LEN(table->locks);
ut_ad(!locked || UT_LIST_GET_FIRST(table->locks)->trx == this);
dict_sys.remove(table, true, locked);
if (locked) {
UT_LIST_ADD_FIRST(lock.evicted_tables, table);
}
}
/****************************************************************//**
Commits a transaction in memory. */
static
void
trx_commit_in_memory(
/*=================*/
trx_t* trx, /*!< in/out: transaction */
const mtr_t* mtr) /*!< in: mini-transaction of
trx_write_serialisation_history(), or NULL if
the transaction did not modify anything */
{
trx->must_flush_log_later = false;
trx->read_view.close();
if (trx_is_autocommit_non_locking(trx)) {
ut_ad(trx->id == 0);
ut_ad(trx->read_only);
ut_a(!trx->is_recovered);
ut_ad(trx->rsegs.m_redo.rseg == NULL);
/* Note: We are asserting without holding the lock mutex. But
that is OK because this transaction is not waiting and cannot
be rolled back and no new locks can (or should) be added
because it is flagged as a non-locking read-only transaction. */
ut_a(UT_LIST_GET_LEN(trx->lock.trx_locks) == 0);
/* This state change is not protected by any mutex, therefore
there is an inherent race here around state transition during
printouts. We ignore this race for the sake of efficiency.
However, the trx_sys_t::mutex will protect the trx_t instance
and it cannot be removed from the trx_list and freed
without first acquiring the trx_sys_t::mutex. */
ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE));
MONITOR_INC(MONITOR_TRX_NL_RO_COMMIT);
DBUG_LOG("trx", "Autocommit in memory: " << trx);
trx->state = TRX_STATE_NOT_STARTED;
} else {
trx->commit_state();
if (trx->id) {
trx_sys.deregister_rw(trx);
/* Wait for any implicit-to-explicit lock
conversions to cease, so that there will be no
race condition in lock_release(). */
while (UNIV_UNLIKELY(trx->is_referenced())) {
ut_delay(srv_spin_wait_delay);
}
trx->release_locks();
trx->id = 0;
} else {
ut_ad(trx->read_only || !trx->rsegs.m_redo.rseg);
trx->release_locks();
}
DEBUG_SYNC_C("after_trx_committed_in_memory");
if (trx->read_only || !trx->rsegs.m_redo.rseg) {
MONITOR_INC(MONITOR_TRX_RO_COMMIT);
} else {
trx_update_mod_tables_timestamp(trx);
MONITOR_INC(MONITOR_TRX_RW_COMMIT);
trx->is_recovered = false;
}
while (dict_table_t* table = UT_LIST_GET_FIRST(
trx->lock.evicted_tables)) {
UT_LIST_REMOVE(trx->lock.evicted_tables, table);
dict_mem_table_free(table);
}
}
ut_ad(!trx->rsegs.m_redo.undo);
ut_ad(UT_LIST_GET_LEN(trx->lock.evicted_tables) == 0);
if (trx_rseg_t* rseg = trx->rsegs.m_redo.rseg) {
mutex_enter(&rseg->mutex);
ut_ad(rseg->trx_ref_count > 0);
--rseg->trx_ref_count;
mutex_exit(&rseg->mutex);
if (trx_undo_t*& insert = trx->rsegs.m_redo.old_insert) {
ut_ad(insert->rseg == rseg);
trx_undo_commit_cleanup(insert, false);
insert = NULL;
}
}
ut_ad(!trx->rsegs.m_redo.old_insert);
if (mtr != NULL) {
if (trx_undo_t*& undo = trx->rsegs.m_noredo.undo) {
ut_ad(undo->rseg == trx->rsegs.m_noredo.rseg);
trx_undo_commit_cleanup(undo, true);
undo = NULL;
}
/* NOTE that we could possibly make a group commit more
efficient here: call os_thread_yield here to allow also other
trxs to come to commit! */
/*-------------------------------------*/
/* Depending on the my.cnf options, we may now write the log
buffer to the log files, making the transaction durable if
the OS does not crash. We may also flush the log files to
disk, making the transaction durable also at an OS crash or a
power outage.
The idea in InnoDB's group commit is that a group of
transactions gather behind a trx doing a physical disk write
to log files, and when that physical write has been completed,
one of those transactions does a write which commits the whole
group. Note that this group commit will only bring benefit if
there are > 2 users in the database. Then at least 2 users can
gather behind one doing the physical log write to disk.
If we are calling trx_commit() under prepare_commit_mutex, we
will delay possible log write and flush to a separate function
trx_commit_complete_for_mysql(), which is only called when the
thread has released the mutex. This is to make the
group commit algorithm to work. Otherwise, the prepare_commit
mutex would serialize all commits and prevent a group of
transactions from gathering. */
lsn_t lsn = mtr->commit_lsn();
if (lsn == 0) {
/* Nothing to be done. */
} else if (trx->flush_log_later) {
/* Do nothing yet */
trx->must_flush_log_later = true;
} else if (srv_flush_log_at_trx_commit == 0) {
/* Do nothing */
} else {
trx_flush_log_if_needed(lsn, trx);
}
trx->commit_lsn = lsn;
/* Tell server some activity has happened, since the trx
does changes something. Background utility threads like
master thread, purge thread or page_cleaner thread might
have some work to do. */
srv_active_wake_master_thread();
}
ut_ad(!trx->rsegs.m_noredo.undo);
/* Free all savepoints, starting from the first. */
trx_named_savept_t* savep = UT_LIST_GET_FIRST(trx->trx_savepoints);
trx_roll_savepoints_free(trx, savep);
if (trx->fts_trx != NULL) {
trx_finalize_for_fts(trx, trx->undo_no != 0);
}
trx_mutex_enter(trx);
trx->dict_operation = TRX_DICT_OP_NONE;
#ifdef WITH_WSREP
trx->lock.was_chosen_as_wsrep_victim = FALSE;
#endif
DBUG_LOG("trx", "Commit in memory: " << trx);
trx->state = TRX_STATE_NOT_STARTED;
assert_trx_is_free(trx);
trx_init(trx);
trx_mutex_exit(trx);
ut_a(trx->error_state == DB_SUCCESS);
if (!srv_read_only_mode) {
srv_wake_purge_thread_if_not_active();
}
}
/** Commit a transaction and a mini-transaction.
@param[in,out] trx transaction
@param[in,out] mtr mini-transaction (NULL if no modifications) */
void trx_commit_low(trx_t* trx, mtr_t* mtr)
{
assert_trx_nonlocking_or_in_list(trx);
ut_ad(!trx_state_eq(trx, TRX_STATE_COMMITTED_IN_MEMORY));
ut_ad(!mtr || mtr->is_active());
ut_d(bool aborted = trx->in_rollback
&& trx->error_state == DB_DEADLOCK);
ut_ad(!mtr == (aborted || !trx->has_logged_or_recovered()));
ut_ad(!mtr || !aborted);
/* undo_no is non-zero if we're doing the final commit. */
if (trx->fts_trx != NULL && trx->undo_no != 0) {
dberr_t error;
ut_a(!trx_is_autocommit_non_locking(trx));
error = fts_commit(trx);
/* FTS-FIXME: Temporarily tolerate DB_DUPLICATE_KEY
instead of dying. This is a possible scenario if there
is a crash between insert to DELETED table committing
and transaction committing. The fix would be able to
return error from this function */
if (error != DB_SUCCESS && error != DB_DUPLICATE_KEY) {
/* FTS-FIXME: once we can return values from this
function, we should do so and signal an error
instead of just dying. */
ut_error;
}
}
#ifndef DBUG_OFF
const bool debug_sync = trx->mysql_thd && trx->has_logged_persistent();
#endif
if (mtr != NULL) {
trx_write_serialisation_history(trx, mtr);
/* The following call commits the mini-transaction, making the
whole transaction committed in the file-based world, at this
log sequence number. The transaction becomes 'durable' when
we write the log to disk, but in the logical sense the commit
in the file-based data structures (undo logs etc.) happens
here.
NOTE that transaction numbers, which are assigned only to
transactions with an update undo log, do not necessarily come
in exactly the same order as commit lsn's, if the transactions
have different rollback segments. To get exactly the same
order we should hold the kernel mutex up to this point,
adding to the contention of the kernel mutex. However, if
a transaction T2 is able to see modifications made by
a transaction T1, T2 will always get a bigger transaction
number and a bigger commit lsn than T1. */
/*--------------*/
mtr_commit(mtr);
DBUG_EXECUTE_IF("ib_crash_during_trx_commit_in_mem",
if (trx->has_logged()) {
log_write_up_to(mtr->commit_lsn(),
true);
DBUG_SUICIDE();
});
/*--------------*/
}
#ifndef DBUG_OFF
/* In case of this function is called from a stack executing
THD::release_resources -> ...
innobase_connection_close() ->
trx_rollback_for_mysql... -> .
mysql's thd does not seem to have
thd->debug_sync_control defined any longer. However the stack
is possible only with a prepared trx not updating any data.
*/
if (debug_sync) {
DEBUG_SYNC_C("before_trx_state_committed_in_memory");
}
#endif
trx_commit_in_memory(trx, mtr);
}
/****************************************************************//**
Commits a transaction. */
void
trx_commit(
/*=======*/
trx_t* trx) /*!< in/out: transaction */
{
mtr_t* mtr;
mtr_t local_mtr;
DBUG_EXECUTE_IF("ib_trx_commit_crash_before_trx_commit_start",
DBUG_SUICIDE(););
if (trx->has_logged_or_recovered()) {
mtr = &local_mtr;
mtr->start();
} else {
mtr = NULL;
}
trx_commit_low(trx, mtr);
#ifdef WITH_WSREP
/* Serialization history has been written and the
transaction is committed in memory, which makes
this commit ordered. Release commit order critical
section. */
if (wsrep_on(trx->mysql_thd))
{
wsrep_commit_ordered(trx->mysql_thd);
}
#endif /* WITH_WSREP */
}
/****************************************************************//**
Prepares a transaction for commit/rollback. */
void
trx_commit_or_rollback_prepare(
/*===========================*/
trx_t* trx) /*!< in/out: transaction */
{
/* We are reading trx->state without holding trx_sys.mutex
here, because the commit or rollback should be invoked for a
running (or recovered prepared) transaction that is associated
with the current thread. */
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
trx_start_low(trx, true);
/* fall through */
case TRX_STATE_ACTIVE:
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
/* If the trx is in a lock wait state, moves the waiting
query thread to the suspended state */
if (trx->lock.que_state == TRX_QUE_LOCK_WAIT) {
ut_a(trx->lock.wait_thr != NULL);
trx->lock.wait_thr->state = QUE_THR_SUSPENDED;
trx->lock.wait_thr = NULL;
trx->lock.que_state = TRX_QUE_RUNNING;
}
ut_a(trx->lock.n_active_thrs == 1);
return;
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
}
ut_error;
}
/*********************************************************************//**
Creates a commit command node struct.
@return own: commit node struct */
commit_node_t*
trx_commit_node_create(
/*===================*/
mem_heap_t* heap) /*!< in: mem heap where created */
{
commit_node_t* node;
node = static_cast<commit_node_t*>(mem_heap_alloc(heap, sizeof(*node)));
node->common.type = QUE_NODE_COMMIT;
node->state = COMMIT_NODE_SEND;
return(node);
}
/***********************************************************//**
Performs an execution step for a commit type node in a query graph.
@return query thread to run next, or NULL */
que_thr_t*
trx_commit_step(
/*============*/
que_thr_t* thr) /*!< in: query thread */
{
commit_node_t* node;
node = static_cast<commit_node_t*>(thr->run_node);
ut_ad(que_node_get_type(node) == QUE_NODE_COMMIT);
if (thr->prev_node == que_node_get_parent(node)) {
node->state = COMMIT_NODE_SEND;
}
if (node->state == COMMIT_NODE_SEND) {
trx_t* trx;
node->state = COMMIT_NODE_WAIT;
trx = thr_get_trx(thr);
ut_a(trx->lock.wait_thr == NULL);
ut_a(trx->lock.que_state != TRX_QUE_LOCK_WAIT);
trx_commit_or_rollback_prepare(trx);
trx->lock.que_state = TRX_QUE_COMMITTING;
trx_commit(trx);
ut_ad(trx->lock.wait_thr == NULL);
trx->lock.que_state = TRX_QUE_RUNNING;
thr = NULL;
} else {
ut_ad(node->state == COMMIT_NODE_WAIT);
node->state = COMMIT_NODE_SEND;
thr->run_node = que_node_get_parent(node);
}
return(thr);
}
/**********************************************************************//**
Does the transaction commit for MySQL.
@return DB_SUCCESS or error number */
dberr_t
trx_commit_for_mysql(
/*=================*/
trx_t* trx) /*!< in/out: transaction */
{
/* Because we do not do the commit by sending an Innobase
sig to the transaction, we must here make sure that trx has been
started. */
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
ut_d(trx->start_file = __FILE__);
ut_d(trx->start_line = __LINE__);
trx_start_low(trx, true);
/* fall through */
case TRX_STATE_ACTIVE:
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
trx->op_info = "committing";
trx_commit(trx);
MONITOR_DEC(MONITOR_TRX_ACTIVE);
trx->op_info = "";
return(DB_SUCCESS);
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
}
ut_error;
return(DB_CORRUPTION);
}
/**********************************************************************//**
If required, flushes the log to disk if we called trx_commit_for_mysql()
with trx->flush_log_later == TRUE. */
void
trx_commit_complete_for_mysql(
/*==========================*/
trx_t* trx) /*!< in/out: transaction */
{
if (trx->id != 0
|| !trx->must_flush_log_later
|| (srv_flush_log_at_trx_commit == 1 && trx->active_commit_ordered)) {
return;
}
trx_flush_log_if_needed(trx->commit_lsn, trx);
trx->must_flush_log_later = false;
}
/**********************************************************************//**
Marks the latest SQL statement ended. */
void
trx_mark_sql_stat_end(
/*==================*/
trx_t* trx) /*!< in: trx handle */
{
ut_a(trx);
switch (trx->state) {
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
case TRX_STATE_NOT_STARTED:
trx->undo_no = 0;
/* fall through */
case TRX_STATE_ACTIVE:
trx->last_sql_stat_start.least_undo_no = trx->undo_no;
if (trx->fts_trx != NULL) {
fts_savepoint_laststmt_refresh(trx);
}
return;
}
ut_error;
}
/**********************************************************************//**
Prints info about a transaction. */
void
trx_print_low(
/*==========*/
FILE* f,
/*!< in: output stream */
const trx_t* trx,
/*!< in: transaction */
ulint max_query_len,
/*!< in: max query length to print,
or 0 to use the default max length */
ulint n_rec_locks,
/*!< in: lock_number_of_rows_locked(&trx->lock) */
ulint n_trx_locks,
/*!< in: length of trx->lock.trx_locks */
ulint heap_size)
/*!< in: mem_heap_get_size(trx->lock.lock_heap) */
{
ibool newline;
const char* op_info;
fprintf(f, "TRANSACTION " TRX_ID_FMT, trx_get_id_for_print(trx));
/* trx->state cannot change from or to NOT_STARTED while we
are holding the trx_sys.mutex. It may change from ACTIVE to
PREPARED or COMMITTED. */
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
fputs(", not started", f);
goto state_ok;
case TRX_STATE_ACTIVE:
fprintf(f, ", ACTIVE %lu sec",
(ulong) difftime(time(NULL), trx->start_time));
goto state_ok;
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
fprintf(f, ", ACTIVE (PREPARED) %lu sec",
(ulong) difftime(time(NULL), trx->start_time));
goto state_ok;
case TRX_STATE_COMMITTED_IN_MEMORY:
fputs(", COMMITTED IN MEMORY", f);
goto state_ok;
}
fprintf(f, ", state %lu", (ulong) trx->state);
ut_ad(0);
state_ok:
/* prevent a race condition */
op_info = trx->op_info;
if (*op_info) {
putc(' ', f);
fputs(op_info, f);
}
if (trx->is_recovered) {
fputs(" recovered trx", f);
}
if (trx->declared_to_be_inside_innodb) {
fprintf(f, ", thread declared inside InnoDB %lu",
(ulong) trx->n_tickets_to_enter_innodb);
}
putc('\n', f);
if (trx->n_mysql_tables_in_use > 0 || trx->mysql_n_tables_locked > 0) {
fprintf(f, "mysql tables in use %lu, locked %lu\n",
(ulong) trx->n_mysql_tables_in_use,
(ulong) trx->mysql_n_tables_locked);
}
newline = TRUE;
/* trx->lock.que_state of an ACTIVE transaction may change
while we are not holding trx->mutex. We perform a dirty read
for performance reasons. */
switch (trx->lock.que_state) {
case TRX_QUE_RUNNING:
newline = FALSE; break;
case TRX_QUE_LOCK_WAIT:
fputs("LOCK WAIT ", f); break;
case TRX_QUE_ROLLING_BACK:
fputs("ROLLING BACK ", f); break;
case TRX_QUE_COMMITTING:
fputs("COMMITTING ", f); break;
default:
fprintf(f, "que state %lu ", (ulong) trx->lock.que_state);
}
if (n_trx_locks > 0 || heap_size > 400) {
newline = TRUE;
fprintf(f, "%lu lock struct(s), heap size %lu,"
" %lu row lock(s)",
(ulong) n_trx_locks,
(ulong) heap_size,
(ulong) n_rec_locks);
}
if (trx->undo_no != 0) {
newline = TRUE;
fprintf(f, ", undo log entries " TRX_ID_FMT, trx->undo_no);
}
if (newline) {
putc('\n', f);
}
if (trx->state != TRX_STATE_NOT_STARTED && trx->mysql_thd != NULL) {
innobase_mysql_print_thd(
f, trx->mysql_thd, static_cast<uint>(max_query_len));
}
}
/**********************************************************************//**
Prints info about a transaction.
The caller must hold lock_sys.mutex.
When possible, use trx_print() instead. */
void
trx_print_latched(
/*==============*/
FILE* f, /*!< in: output stream */
const trx_t* trx, /*!< in: transaction */
ulint max_query_len) /*!< in: max query length to print,
or 0 to use the default max length */
{
ut_ad(lock_mutex_own());
trx_print_low(f, trx, max_query_len,
lock_number_of_rows_locked(&trx->lock),
UT_LIST_GET_LEN(trx->lock.trx_locks),
mem_heap_get_size(trx->lock.lock_heap));
}
/**********************************************************************//**
Prints info about a transaction.
Acquires and releases lock_sys.mutex. */
void
trx_print(
/*======*/
FILE* f, /*!< in: output stream */
const trx_t* trx, /*!< in: transaction */
ulint max_query_len) /*!< in: max query length to print,
or 0 to use the default max length */
{
ulint n_rec_locks;
ulint n_trx_locks;
ulint heap_size;
lock_mutex_enter();
n_rec_locks = lock_number_of_rows_locked(&trx->lock);
n_trx_locks = UT_LIST_GET_LEN(trx->lock.trx_locks);
heap_size = mem_heap_get_size(trx->lock.lock_heap);
lock_mutex_exit();
trx_print_low(f, trx, max_query_len,
n_rec_locks, n_trx_locks, heap_size);
}
/*******************************************************************//**
Compares the "weight" (or size) of two transactions. Transactions that
have edited non-transactional tables are considered heavier than ones
that have not.
@return TRUE if weight(a) >= weight(b) */
bool
trx_weight_ge(
/*==========*/
const trx_t* a, /*!< in: transaction to be compared */
const trx_t* b) /*!< in: transaction to be compared */
{
ibool a_notrans_edit;
ibool b_notrans_edit;
/* If mysql_thd is NULL for a transaction we assume that it has
not edited non-transactional tables. */
a_notrans_edit = a->mysql_thd != NULL
&& thd_has_edited_nontrans_tables(a->mysql_thd);
b_notrans_edit = b->mysql_thd != NULL
&& thd_has_edited_nontrans_tables(b->mysql_thd);
if (a_notrans_edit != b_notrans_edit) {
return(a_notrans_edit);
}
/* Either both had edited non-transactional tables or both had
not, we fall back to comparing the number of altered/locked
rows. */
return(TRX_WEIGHT(a) >= TRX_WEIGHT(b));
}
/** Prepare a transaction.
@return log sequence number that makes the XA PREPARE durable
@retval 0 if no changes needed to be made durable */
static
lsn_t
trx_prepare_low(trx_t* trx)
{
ut_ad(!trx->rsegs.m_redo.old_insert);
ut_ad(!trx->is_recovered);
mtr_t mtr;
if (trx_undo_t* undo = trx->rsegs.m_noredo.undo) {
ut_ad(undo->rseg == trx->rsegs.m_noredo.rseg);
mtr.start();
mtr.set_log_mode(MTR_LOG_NO_REDO);
mutex_enter(&undo->rseg->mutex);
trx_undo_set_state_at_prepare(trx, undo, false, &mtr);
mutex_exit(&undo->rseg->mutex);
mtr.commit();
}
trx_undo_t* undo = trx->rsegs.m_redo.undo;
if (!undo) {
/* There were no changes to persistent tables. */
return(0);
}
trx_rseg_t* rseg = trx->rsegs.m_redo.rseg;
ut_ad(undo->rseg == rseg);
mtr.start();
/* Change the undo log segment states from TRX_UNDO_ACTIVE to
TRX_UNDO_PREPARED: these modifications to the file data
structure define the transaction as prepared in the file-based
world, at the serialization point of lsn. */
mutex_enter(&rseg->mutex);
trx_undo_set_state_at_prepare(trx, undo, false, &mtr);
mutex_exit(&rseg->mutex);
/* Make the XA PREPARE durable. */
mtr.commit();
ut_ad(mtr.commit_lsn() > 0);
return(mtr.commit_lsn());
}
/****************************************************************//**
Prepares a transaction. */
static
void
trx_prepare(
/*========*/
trx_t* trx) /*!< in/out: transaction */
{
/* Only fresh user transactions can be prepared.
Recovered transactions cannot. */
ut_a(!trx->is_recovered);
lsn_t lsn = trx_prepare_low(trx);
DBUG_EXECUTE_IF("ib_trx_crash_during_xa_prepare_step", DBUG_SUICIDE(););
ut_a(trx->state == TRX_STATE_ACTIVE);
trx_mutex_enter(trx);
trx->state = TRX_STATE_PREPARED;
trx_mutex_exit(trx);
if (lsn) {
/* Depending on the my.cnf options, we may now write the log
buffer to the log files, making the prepared state of the
transaction durable if the OS does not crash. We may also
flush the log files to disk, making the prepared state of the
transaction durable also at an OS crash or a power outage.
The idea in InnoDB's group prepare is that a group of
transactions gather behind a trx doing a physical disk write
to log files, and when that physical write has been completed,
one of those transactions does a write which prepares the whole
group. Note that this group prepare will only bring benefit if
there are > 2 users in the database. Then at least 2 users can
gather behind one doing the physical log write to disk.
We must not be holding any mutexes or latches here. */
trx_flush_log_if_needed(lsn, trx);
}
}
/** XA PREPARE a transaction.
@param[in,out] trx transaction to prepare */
void trx_prepare_for_mysql(trx_t* trx)
{
trx_start_if_not_started_xa(trx, false);
trx->op_info = "preparing";
trx_prepare(trx);
trx->op_info = "";
}
struct trx_recover_for_mysql_callback_arg
{
XID *xid_list;
uint len;
uint count;
};
static my_bool trx_recover_for_mysql_callback(rw_trx_hash_element_t *element,
trx_recover_for_mysql_callback_arg *arg)
{
DBUG_ASSERT(arg->len > 0);
mutex_enter(&element->mutex);
if (trx_t *trx= element->trx)
{
/*
The state of a read-write transaction can only change from ACTIVE to
PREPARED while we are holding the element->mutex. But since it is
executed at startup no state change should occur.
*/
if (trx_state_eq(trx, TRX_STATE_PREPARED))
{
ut_ad(trx->is_recovered);
ut_ad(trx->id);
if (arg->count == 0)
ib::info() << "Starting recovery for XA transactions...";
XID& xid= arg->xid_list[arg->count];
if (arg->count++ < arg->len)
{
trx->state= TRX_STATE_PREPARED_RECOVERED;
ib::info() << "Transaction " << trx->id
<< " in prepared state after recovery";
ib::info() << "Transaction contains changes to " << trx->undo_no
<< " rows";
xid= *trx->xid;
}
}
}
mutex_exit(&element->mutex);
/* Do not terminate upon reaching arg->len; count all transactions */
return false;
}
static my_bool trx_recover_reset_callback(rw_trx_hash_element_t *element,
void*)
{
mutex_enter(&element->mutex);
if (trx_t *trx= element->trx)
{
if (trx_state_eq(trx, TRX_STATE_PREPARED_RECOVERED))
trx->state= TRX_STATE_PREPARED;
}
mutex_exit(&element->mutex);
return false;
}
/**
Find prepared transaction objects for recovery.
@param[out] xid_list prepared transactions
@param[in] len number of slots in xid_list
@return number of prepared transactions stored in xid_list
*/
int trx_recover_for_mysql(XID *xid_list, uint len)
{
trx_recover_for_mysql_callback_arg arg= { xid_list, len, 0 };
ut_ad(xid_list);
ut_ad(len);
/* Fill xid_list with PREPARED transactions. */
trx_sys.rw_trx_hash.iterate_no_dups(reinterpret_cast<my_hash_walk_action>
(trx_recover_for_mysql_callback), &arg);
if (arg.count)
{
ib::info() << arg.count
<< " transactions in prepared state after recovery";
/* After returning the full list, reset the state, because
init_server_components() wants to recover the collection of
transactions twice, by first calling tc_log->open() and then
ha_recover() directly. */
if (arg.count <= len)
trx_sys.rw_trx_hash.iterate(reinterpret_cast<my_hash_walk_action>
(trx_recover_reset_callback), NULL);
}
return int(std::min(arg.count, len));
}
struct trx_get_trx_by_xid_callback_arg
{
const XID *xid;
trx_t *trx;
};
static my_bool trx_get_trx_by_xid_callback(rw_trx_hash_element_t *element,
trx_get_trx_by_xid_callback_arg *arg)
{
my_bool found= 0;
mutex_enter(&element->mutex);
if (trx_t *trx= element->trx)
{
trx_mutex_enter(trx);
if (trx->is_recovered &&
(trx_state_eq(trx, TRX_STATE_PREPARED) ||
trx_state_eq(trx, TRX_STATE_PREPARED_RECOVERED)) &&
arg->xid->eq(reinterpret_cast<XID*>(trx->xid)))
{
#ifdef WITH_WSREP
/* The commit of a prepared recovered Galera
transaction needs a valid trx->xid for
invoking trx_sys_update_wsrep_checkpoint(). */
if (!wsrep_is_wsrep_xid(trx->xid))
#endif /* WITH_WSREP */
/* Invalidate the XID, so that subsequent calls will not find it. */
trx->xid->null();
arg->trx= trx;
found= 1;
}
trx_mutex_exit(trx);
}
mutex_exit(&element->mutex);
return found;
}
/** Look up an X/Open distributed transaction in XA PREPARE state.
@param[in] xid X/Open XA transaction identifier
@return transaction on match (the trx_t::xid will be invalidated);
note that the trx may have been committed before the caller acquires
trx_t::mutex
@retval NULL if no match */
trx_t* trx_get_trx_by_xid(const XID* xid)
{
trx_get_trx_by_xid_callback_arg arg= { xid, 0 };
if (xid)
trx_sys.rw_trx_hash.iterate(reinterpret_cast<my_hash_walk_action>
(trx_get_trx_by_xid_callback), &arg);
return arg.trx;
}
/*************************************************************//**
Starts the transaction if it is not yet started. */
void
trx_start_if_not_started_xa_low(
/*============================*/
trx_t* trx, /*!< in/out: transaction */
bool read_write) /*!< in: true if read write transaction */
{
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
trx_start_low(trx, read_write);
return;
case TRX_STATE_ACTIVE:
if (trx->id == 0 && read_write) {
/* If the transaction is tagged as read-only then
it can only write to temp tables and for such
transactions we don't want to move them to the
trx_sys_t::rw_trx_hash. */
if (!trx->read_only) {
trx_set_rw_mode(trx);
}
}
return;
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
}
ut_error;
}
/*************************************************************//**
Starts the transaction if it is not yet started. */
void
trx_start_if_not_started_low(
/*==========================*/
trx_t* trx, /*!< in: transaction */
bool read_write) /*!< in: true if read write transaction */
{
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
trx_start_low(trx, read_write);
return;
case TRX_STATE_ACTIVE:
if (read_write && trx->id == 0 && !trx->read_only) {
trx_set_rw_mode(trx);
}
return;
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
}
ut_error;
}
/*************************************************************//**
Starts a transaction for internal processing. */
void
trx_start_internal_low(
/*===================*/
trx_t* trx) /*!< in/out: transaction */
{
/* Ensure it is not flagged as an auto-commit-non-locking
transaction. */
trx->will_lock = 1;
trx->internal = true;
trx_start_low(trx, true);
}
/** Starts a read-only transaction for internal processing.
@param[in,out] trx transaction to be started */
void
trx_start_internal_read_only_low(
trx_t* trx)
{
/* Ensure it is not flagged as an auto-commit-non-locking
transaction. */
trx->will_lock = 1;
trx->internal = true;
trx_start_low(trx, false);
}
/*************************************************************//**
Starts the transaction for a DDL operation. */
void
trx_start_for_ddl_low(
/*==================*/
trx_t* trx, /*!< in/out: transaction */
trx_dict_op_t op) /*!< in: dictionary operation type */
{
switch (trx->state) {
case TRX_STATE_NOT_STARTED:
/* Flag this transaction as a dictionary operation, so that
the data dictionary will be locked in crash recovery. */
trx_set_dict_operation(trx, op);
/* Ensure it is not flagged as an auto-commit-non-locking
transation. */
trx->will_lock = 1;
trx->ddl= true;
trx_start_internal_low(trx);
return;
case TRX_STATE_ACTIVE:
case TRX_STATE_PREPARED:
case TRX_STATE_PREPARED_RECOVERED:
case TRX_STATE_COMMITTED_IN_MEMORY:
break;
}
ut_error;
}
/*************************************************************//**
Set the transaction as a read-write transaction if it is not already
tagged as such. Read-only transactions that are writing to temporary
tables are assigned an ID and a rollback segment but are not added
to the trx read-write list because their updates should not be visible
to other transactions and therefore their changes can be ignored by
by MVCC. */
void
trx_set_rw_mode(
/*============*/
trx_t* trx) /*!< in/out: transaction that is RW */
{
ut_ad(trx->rsegs.m_redo.rseg == 0);
ut_ad(!trx_is_autocommit_non_locking(trx));
ut_ad(!trx->read_only);
ut_ad(trx->id == 0);
if (high_level_read_only) {
return;
}
/* Function is promoting existing trx from ro mode to rw mode.
In this process it has acquired trx_sys.mutex as it plan to
move trx from ro list to rw list. If in future, some other thread
looks at this trx object while it is being promoted then ensure
that both threads are synced by acquring trx->mutex to avoid decision
based on in-consistent view formed during promotion. */
trx->rsegs.m_redo.rseg = trx_assign_rseg_low();
ut_ad(trx->rsegs.m_redo.rseg != 0);
trx_sys.register_rw(trx);
/* So that we can see our own changes. */
if (trx->read_view.is_open()) {
trx->read_view.set_creator_trx_id(trx->id);
}
}
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