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trx0trx.c:

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Fix bug: group commit still did not work when we had MySQL binlogging on


innobase/trx/trx0trx.c:
  Fix bug: group commit still did not work when we had MySQL binlogging on
This commit is contained in:
unknown 2003-07-03 17:36:33 +03:00
parent dc0fb6ea48
commit fd0ecf1e47
1 changed files with 64 additions and 28 deletions
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88
innobase/trx/trx0trx.c
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@ -778,29 +778,53 @@ trx_commit_off_kernel(
efficient here: call os_thread_yield here to allow also other
trxs to come to commit! */
/* We now flush the log, as the transaction made changes to
the database, making the transaction committed on disk. It is
enough that any one of the log groups gets written to disk. */
/*-------------------------------------*/
/* Most MySQL users run with srv_flush_.. set to 0: */
/* 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.
if (srv_flush_log_at_trx_commit != 0) {
if (srv_unix_file_flush_method != SRV_UNIX_NOSYNC
&& srv_flush_log_at_trx_commit != 2
&& !trx->flush_log_later) {
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.
/* Write the log to the log files AND flush
them to disk */
If we are calling trx_commit() under MySQL's binlog 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 binlog mutex. This is to make the
group commit algorithm to work. Otherwise, the MySQL binlog
mutex would serialize all commits and prevent a group of
transactions from gathering. */
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, TRUE);
} else {
/* Write the log but do not flush it to disk */
if (trx->flush_log_later) {
/* Do nothing yet */
} else if (srv_flush_log_at_trx_commit == 0) {
/* Do nothing */
} else if (srv_flush_log_at_trx_commit == 1) {
if (srv_unix_file_flush_method == SRV_UNIX_NOSYNC) {
/* Write the log but do not flush it to disk */
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, FALSE);
}
}
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, FALSE);
} else {
/* Write the log to the log files AND flush
them to disk */
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, TRUE);
}
} else if (srv_flush_log_at_trx_commit == 2) {
/* Write the log but do not flush it to disk */
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, FALSE);
} else {
ut_a(0);
}
trx->commit_lsn = lsn;
@ -1497,21 +1521,33 @@ trx_commit_complete_for_mysql(
/* out: 0 or error number */
trx_t* trx) /* in: trx handle */
{
ut_a(trx);
dulint lsn = trx->commit_lsn;
if (srv_flush_log_at_trx_commit == 1
&& srv_unix_file_flush_method != SRV_UNIX_NOSYNC) {
ut_a(trx);
trx->op_info = (char *) "flushing log";
if (srv_flush_log_at_trx_commit == 0) {
/* Do nothing */
} else if (srv_flush_log_at_trx_commit == 1) {
if (srv_unix_file_flush_method == SRV_UNIX_NOSYNC) {
/* Write the log but do not flush it to disk */
/* Flush the log files to disk */
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, FALSE);
} else {
/* Write the log to the log files AND flush them to
disk */
log_write_up_to(trx->commit_lsn, LOG_WAIT_ONE_GROUP, TRUE);
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, TRUE);
}
} else if (srv_flush_log_at_trx_commit == 2) {
trx->op_info = (char *) "";
}
/* Write the log but do not flush it to disk */
return(0);
log_write_up_to(lsn, LOG_WAIT_ONE_GROUP, FALSE);
} else {
ut_a(0);
}
return(0);
}
/**************************************************************************