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| author | Alfranio Correia <alfranio.correia@sun.com> | 2009-09-29 15:40:52 +0100 |
|---|---|---|
| committer | Alfranio Correia <alfranio.correia@sun.com> | 2009-09-29 15:40:52 +0100 |
| commit | 3ab71376ceb2d5da81d3b6fb092630d0b0929d76 (patch) | |
| tree | 5227fe1804bac85dca21ad7baf732306e7d30679 /sql/set_var.h | |
| parent | 0110bd04d24503d84df93d31b444586c4137c98c (diff) | |
| download | mariadb-git-3ab71376ceb2d5da81d3b6fb092630d0b0929d76.tar.gz | |
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.
Diffstat (limited to 'sql/set_var.h')
| -rw-r--r-- | sql/set_var.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/sql/set_var.h b/sql/set_var.h index 02c87abed88..0202a15836d 100644 --- a/sql/set_var.h +++ b/sql/set_var.h @@ -178,10 +178,10 @@ public: /** Unsigned int system variable class */ -class sys_var_int_ptr :public sys_var +class sys_var_uint_ptr :public sys_var { public: - sys_var_int_ptr(sys_var_chain *chain, const char *name_arg, + sys_var_uint_ptr(sys_var_chain *chain, const char *name_arg, uint *value_ptr_arg, sys_after_update_func after_update_arg= NULL) :sys_var(name_arg, after_update_arg), |