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MDEV-34705: Binlog-in-engine: Crash-safe slave

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This patch makes replication crash-safe with the new binlog implementation,
even when --innodb-flush-log-at-trx-commit=0|2. The point is to not send any
binlog events to the slave until they have become durable on master, thus
avoiding that a slave may replicate a transaction that is lost during master
recovery, diverging the slave from the master.

Keep track of which point in the binlog has been durably synced to disk
(meaning the corresponding LSN has been durably synced to disk in the InnoDB
redo log). Each write to the binlog inserts an entry with offset and
corresponding LSN in a FIFO. Dump threads will first read only up to the
durable point in the binlog. A dump thread will then check the LSN fifo, and
do an InnoDB redo log sync if anything is pending. Then the FIFO is emptied
of any LSNs that have now become durable, and the durable point in the
binlog is updated and reading the binlog can continue.

Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
This commit is contained in:
Kristian Nielsen
2025-07-01 15:07:03 +02:00
parent baec2064a1
commit d26851a575
33 changed files with 851 additions and 149 deletions
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23
sql/sql_repl.cc
View File

@@ -2568,7 +2568,7 @@ static int init_binlog_sender(binlog_send_info *info,
/* ToDo: Need more complex logic here. I want to be able to at least switch from legacy to innodb binlog without having to RESET MASTER. So we need to be able to start reading from legacy and then switch over to the binlog in innodb. Also, we might want to pass the init GTID position in so that the binlog reader can find the place to start by itself? But probably still want to allocate the reader here like this. */
if (opt_binlog_engine_hton &&
!(info->engine_binlog_reader=
(*opt_binlog_engine_hton->get_binlog_reader)()))
(*opt_binlog_engine_hton->get_binlog_reader)(true)))
{
LEX_CSTRING *engine_name= hton_name(opt_binlog_engine_hton);
my_error(ER_CANNOT_INIT_ENGINE_BINLOG_READER, MYF(0), engine_name->str);
@@ -3345,8 +3345,6 @@ static int send_engine_events(binlog_send_info *info, LOG_INFO* linfo)
if (error == LOG_READ_EOF)
{
PSI_stage_info old_stage;
/**
* check if we should wait for more data
*/
@@ -3367,23 +3365,15 @@ static int send_engine_events(binlog_send_info *info, LOG_INFO* linfo)
return 1;
}
mysql_bin_log.lock_binlog_end_pos();
info->thd->ENTER_COND(mysql_bin_log.get_bin_log_cond(),
mysql_bin_log.get_binlog_end_pos_lock(),
&stage_master_has_sent_all_binlog_to_slave,
&old_stage);
while (!should_stop(info, true) &&
!reader->data_available())
while (!should_stop(info, true) && !reader->data_available())
{
//DBUG_ASSERT(!info->heartbeat_period /* ToDo: Implement support for heartbeat events while waiting for more data. */);
int ret= mysql_bin_log.wait_for_update_binlog_end_pos(info->thd, NULL);
if (ret != 0 && ret != ETIMEDOUT && ret != ETIME)
bool ret= reader->wait_available(info->thd, nullptr /* ToDo hearthbeat period. */);
if (ret)
{
ret= 1; // error
break;
// ToDo Hearthbeat sending
}
}
info->thd->EXIT_COND(&old_stage);
continue;
}
@@ -4853,7 +4843,8 @@ show_engine_binlog_events(THD* thd, Protocol *protocol, LEX_MASTER_INFO *lex_mi)
DBUG_ASSERT(opt_binlog_engine_hton);
DBUG_ASSERT(thd->lex->sql_command == SQLCOM_SHOW_BINLOG_EVENTS);
handler_binlog_reader *reader= (*opt_binlog_engine_hton->get_binlog_reader)();
handler_binlog_reader *reader=
(*opt_binlog_engine_hton->get_binlog_reader)(false);
if (!reader)
{
my_error(ER_OUT_OF_RESOURCES, MYF(0));