maria-developers team mailing list archive

[Kristian Nielsen <knielsen@xxxxxxxxxxxxxxx>]

Michael Widenius <monty@xxxxxxxxxxxx> writes:

> knielsen> +++ b/sql/log.cc	2010-10-04 10:48:08 +0000
> knielsen> @@ -6531,6 +6531,39 @@ err1:
> knielsen>                    "--tc-heuristic-recover={commit|rollback}");
> knielsen>    return 1;
> knielsen>  }
> knielsen> +
> knielsen> +static TC_LOG *
> knielsen> +tc_log_mmap_register(void *arg __attribute__((unused)), int yield)
> knielsen> +{
> knielsen> +  if (yield || total_ha_2pc <= 1)
> knielsen> +    return NULL;
> knielsen> +
> knielsen> +  return &tc_log_mmap;
> knielsen> +}
>
> <cut>
>
> knielsen> +++ b/sql/mysqld.cc	2010-10-04 10:48:08 +0000
> knielsen> @@ -4283,10 +4283,11 @@ a file name for --log-bin-index option",
> knielsen>    }
> knielsen>  #endif
>  
> knielsen> -  tc_log= (total_ha_2pc > 1 ? (opt_bin_log  ?
> knielsen> -                               (TC_LOG *) &mysql_bin_log :
> knielsen> -                               (TC_LOG *) &tc_log_mmap) :
> knielsen> -           (TC_LOG *) &tc_log_dummy);
>
> According to the old code, the tc_log_mmap_register() should use:
>
> if (yield || total_ha_2pc <= 1 || opt_bin_log)
>   return NULL;
>
> Was this an intentional change ?

It is not a behavior change. If opt_bin_log is set, then in the first round
(yield==true), the mmap plugin will yield, and the binlog plugin will select
itself as TC. If opt_bin_log is not set, then binlog plugin will not register
as TC and mmap (or dummy) will register themselves as fallback TC in the
second round (yield==false).

The idea is to generalise the test to handle the case of a custom binlog
plugin, in which case a hard-coded check of opt_bin_log is not sufficient.

> If yes, there should have been a comment about it.

Thanks for your remarks, I will try to clarify the comments.

 - Kristian.