pbxt-discuss team mailing list archive

[MARK CALLAGHAN <mdcallag@xxxxxxxxx>]

I have this in my.cnf ...
pbxt_index_cache_size=20G
pbxt_record_cache_size=40G
pbxt_flush_log_at_trx_commit=2

but at runtime pbxt reports:
pbxt_index_cache_size   32MB
pbxt_record_cache_size  32MB

Which makes sense as these appear to be read-only in ha_pbxt.cc from release 1.1

static MYSQL_SYSVAR_STR(index_cache_size, pbxt_index_cache_size,
  PLUGIN_VAR_READONLY,
  "The amount of memory allocated to the index cache, used only to
cache index data.",
  NULL, NULL, NULL);


On Mon, Nov 1, 2010 at 7:02 AM, MARK CALLAGHAN <mdcallag@xxxxxxxxx> wrote:
> On Sat, Oct 30, 2010 at 9:19 AM, Paul McCullagh
> <paul.mccullagh@xxxxxxxxx> wrote:
>> Hi Mark,
>>
>> What has happened here is the index cache is full of dirty pages, and needs
>> to be flushed.
>>
>> When a thread hits this situation it starts a background thread to flush the
>> indexes. That is why we have xt_wait_for_async_tasks() in the top-most stack
>> trace.
>>
>> The background tasks are all busy flushing the indexes. One of the problems
>> here is that indexes are actually synced to disk before anything can
>> continue (although this is unnecessary for an import - but there is no way
>> to tell PBXT that this is the case).
>>
>> Also, writing an index is "all-or-nothing" so since about 20 GB of index
>> data is dirty it probably all has to be written.
>
> These stacks occur long before the database files are 20G on disk.
>
> --
> Mark Callaghan
> mdcallag@xxxxxxxxx
>



-- 
Mark Callaghan
mdcallag@xxxxxxxxx