mariadb

Tree: 737910fb11

Commit Graph

Author	SHA1	Message	Date
Alfranio Correia	3ab71376ce	BUG#40337 Fsyncing master and relay log to disk after every event is too slow NOTE: Backporting the patch to next-mr. The fix proposed in BUG#35542 and BUG#31665 introduces a performance issue when fsyncing the master.info, relay.info and relay-log.bin* after #th events. Although such solution has been proposed to reduce the probability of corrupted files due to a slave-crash, the performance penalty introduced by it has made the approach impractical for highly intensive workloads. In a nutshell, the option --syn-relay-log proposed in BUG#35542 and BUG#31665 simultaneously fsyncs master.info, relay-log.info and relay-log.bin* and this is the main source of performance issues. This patch introduces new options that give more control to the user on what should be fsynced and how often: 1) (--sync-master-info, integer) which syncs the master.info after #th event; 2) (--sync-relay-log, integer) which syncs the relay-log.bin* after #th events. 3) (--sync-relay-log-info, integer) which syncs the relay.info after #th transactions. To provide both performance and increased reliability, we recommend the following setup: 1) --sync-master-info = 0 eventually the operating system will fsync it; 2) --sync-relay-log = 0 eventually the operating system will fsync it; 3) --sync-relay-log-info = 1 fsyncs it after every transaction; Notice, that the previous setup does not reduce the probability of corrupted master.info and relay-log.bin. To overcome the issue, this patch also introduces a recovery mechanism that right after restart throws away relay-log.bin retrieved from a master and updates the master.info based on the relay.info: 4) (--relay-log-recovery, boolean) which enables a recovery mechanism that throws away relay-log.bin* after a crash. However, it can only recover the incorrect binlog file and position in master.info, if other informations (host, port password, etc) are corrupted or incorrect, then this recovery mechanism will fail to work.	16 years ago

Author

SHA1

Message

Date

Alfranio Correia

3ab71376ce

BUG#40337 Fsyncing master and relay log to disk after every event is too slow

NOTE: Backporting the patch to next-mr.
      
The fix proposed in BUG#35542 and BUG#31665 introduces a performance issue
when fsyncing the master.info, relay.info and relay-log.bin* after #th events.
Although such solution has been proposed to reduce the probability of corrupted
files due to a slave-crash, the performance penalty introduced by it has
made the approach impractical for highly intensive workloads.
      
In a nutshell, the option --syn-relay-log proposed in BUG#35542 and BUG#31665
simultaneously fsyncs master.info, relay-log.info and relay-log.bin* and
this is the main source of performance issues.
      
This patch introduces new options that give more control to the user on
what should be fsynced and how often:
      
   1) (--sync-master-info, integer) which syncs the master.info after #th event;
   2) (--sync-relay-log, integer) which syncs the relay-log.bin* after #th
   events.
   3) (--sync-relay-log-info, integer) which syncs the relay.info after #th
   transactions.
      
   To provide both performance and increased reliability, we recommend the following
   setup:
      
   1) --sync-master-info = 0 eventually the operating system will fsync it;
   2) --sync-relay-log = 0 eventually the operating system will fsync it;
   3) --sync-relay-log-info = 1 fsyncs it after every transaction;
      
Notice, that the previous setup does not reduce the probability of
corrupted master.info and relay-log.bin*. To overcome the issue, this patch also
introduces a recovery mechanism that right after restart throws away relay-log.bin*
retrieved from a master and updates the master.info based on the relay.info:
      
      
   4) (--relay-log-recovery, boolean) which enables a recovery mechanism that
   throws away relay-log.bin* after a crash.
      
However, it can only recover the incorrect binlog file and position in master.info,
if other informations (host, port password, etc) are corrupted or incorrect,
then this recovery mechanism will fail to work.

16 years ago

1 Commits (737910fb11e0fe8d2628bf8091c3a7b0de194db2)