[Mondrian] Flushing SegmentCache

Pedro Alves pmgalves at gmail.com
Thu Feb 16 11:53:24 EST 2012



Quick feedback - It's working great against 3.4 and we were able to hack 
around the 3.3 issues \o/


Thank guys


-pedro



On 02/13/2012 08:59 PM, Luc Boudreau wrote:
> I'm saying we have found some issues with the cache management code in
> 3.3.X, but it should still work (except a few corner cases). Please
> log a Jira case with as much information and reproducible tests as you
> can so we can look into your issue. Regardless of the fact that it
> works on 3.3 or not, I'd like to make sure we fixed the problem for
> the next release.
>
> Also, just a heads up. We have modified the SegmentCache SPI and
> simplified it greatly for the next release. For one thing, you won't
> need to implement the SPI using Java Futures, nor will you need to
> implement SegmentCache.flush() on the SPI side (Mondrian will take
> care of that). I strongly suggest that you take a look at the next
> version of the SPI; it might make your life that much easier.
>
> http://perforce.eigenbase.org:8080/@rev1=head@//open/mondrian/src/main/mondrian/spi/SegmentCache.java
>
> Please also note that the next version of the SPI includes a
> SegmentCacheListener system. Your cache implementation should make use
> of it for optimal performance. Mondrian will call
> SegmentCache.addListener() at runtime and will register a listener
> object with your implementation. This makes Mondrian much more
> efficient in maintaining an index of the contents of the external
> caches by using deltas to figure out how to sync up the segment
> indexes. Listeners and near-real-time updates of the indexes helps
> Mondrian perform in-memory rollups of your cell data (this is an order
> of magnitude more efficient than SQL access). I know, it sounds pretty
> hermetic and complicated. We still haven't had the chance to write a
> neat blog post to explain it all yet.
>
> Bottom line: I suggest you invest the little time necessary to develop
> your code against 3.4.0. The new&  improved SegmentCache SPI is most
> likely the one we will support long-term wise. Version 3.4.0 is almost
> out of the door, so the transition should be as smooth as can be.
>
> Cheers!
>
> Luc
>
>
> On Mon, Feb 13, 2012 at 3:07 PM, Pedro Alves<pmgalves at gmail.com>  wrote:
>>
>> This is for a plugin we want to release for 3.3 also, earlier if possible.
>>
>> Are you saying that it's not possible to do selective cache clearing at all
>> :-(
>>
>>
>>
>> -pedro
>>
>>
>> Luc Boudreau<lucboudreau at gmail.com>  wrote:
>>>
>>> For our next release (due some time in March) we have modified
>>> substantially the code which manages segments and cell data. I remember
>>> seeing that issue, so I suggest you grab the latest binary build off our CI
>>> server and see if it is gone.
>>>
>>> If not,  please log a jira case (with a test case on Foodmart preferably).
>>>
>>> Luc
>>>
>>> On Feb 13, 2012 2:26 PM, "Tiago Ferreira"<tiago.ferreira at webdetails.pt>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I'm using a custom SegmentCache implementation in mondrian 3.3.
>>>> Using cacheControl.flush(cacheControl.createMeasuresRegion(cube)) as in
>>>> the examples in http://mondrian.pentaho.com/documentation/cache_control.php
>>>> for flushing a cube, my SegmentCache's flush method always gets invoked with
>>>> an empty ConstrainedColumn[] and segments aren't removed.
>>>> Any clues on what I might be doing wrong (or not getting)?
>>>>
>>>> Thanks
>>>>
>>>> --
>>>> Tiago G.F.
>>>>
>>>>
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>>>>
>>
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