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From Ian Maxon <ima...@uci.edu>
Subject Re: Yet another storage cleanup and a bit of history
Date Thu, 11 May 2017 03:06:12 GMT
I don't really see how that would require any less intervention than
the current job. As it stands, once it's decided that breaking the
storage for a patch is fine, all we need to do is override the -1
Verified and merge it. What it checks against is HEAD and HEAD~1 of
the patch, not the release version.

On Wed, May 10, 2017 at 7:59 PM, abdullah alamoudi <bamousaa@gmail.com> wrote:
> A follow up on this. So this change has been through a round of review and will be merged
soon. Currently, it fails the storage check test. The storage check test works as follow:
>
> It builds some artifacts using the previous asterixdb version and then tries to read
them using the build with the change. The test itself is good as it catches those changes
that modifies the storage files but not very convenient as one has to have access to jenkins
to override them.
> What I propose is to disable this test and have binary data files with a test that reads
them. If a change changes any storage related classes, then it will still fail those tests
until the files are updated. At which point, the reviewer should catch that and if it is a
legitimate change, then it should be allowed in.
>
> Eventually, we should have backward compatibility storage and/or a migration facility
and then maybe we can put those back on jenkins.
>
> Thoughts? Proposals?
>
>
>> On May 8, 2017, at 10:59 PM, abdullah alamoudi <bamousaa@gmail.com> wrote:
>>
>> Devs,
>> For some time, out storage code has been suffering from incremental design changes
through additional use cases that come along research projects.
>> We have done some cleanup but the code base still suffered from lots of duplicate
code and unneeded work (for both developers and CPUs).
>>
>> One thing we used to do is whenever we need to access an index, we have to create
its "IDataflowHelperFactory". This object will contain most things that defines the index.
Interestingly, it didn't contain all that is needed.
>> For some obscure reason, typeTraits, comparatorFactories, and bloomFilterKeyFields
were places in TreeIndexCreateOperatorDescriptor.
>> Different indexes had different dataflow helpers and so sometimes, multiple class
definitions are needed for operators per index type. and this leads to further bloat of the
system's code.
>>
>> If one thinks about it, the index related objects that are needed during index construction
are only needed when the index gets created. Further needs to access the index for any reason
should only gets the index key (the path in this case).
>> In fact, if one follows the execution of the code, they will see that that is exactly
what is needed and that whenever we try to search/insert/delete/upsert/bulkload, we recompute
many artifacts that end up being useless.
>>
>> So, I proposed a change that fixes this part. Index related objects are only provided
at index creation time and for index access, only the index path is required. This is done
by removing the create method from the IIndexDataflowHelper interface and moving it to IIndexBuilder.
>> With this, all implementations of IIndexDataflowHelper are now in a single class
that basically uses the path to fetch the index on a Node Controller.
>>
>> This change gets rid of more than 3000 lines of code and makes things much cleaner.
Classes that should go to hyracks are moved to hyracks. Asterix related information such as
dataset id and partition number are kept in asterix through the introduction of DatasetLocalResource.
To show the effect of this change, you can look at an example in https://asterix-gerrit.ics.uci.edu/#/c/1728/3/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/algebra/operators/physical/InvertedIndexPOperator.java
<https://asterix-gerrit.ics.uci.edu/#/c/1728/3/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/algebra/operators/physical/InvertedIndexPOperator.java>
>>
>> Look at the amount of work that was unneeded to access an inverted index. The only
thing that was actually needed is the index FileSplitProvider. Take another look at https://asterix-gerrit.ics.uci.edu/#/c/1728/3/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/declared/MetadataProvider.java
<https://asterix-gerrit.ics.uci.edu/#/c/1728/3/asterixdb/asterix-metadata/src/main/java/org/apache/asterix/metadata/declared/MetadataProvider.java>
and see how much unneeded code gets removed. This is not enough on the asterixdb side but
it creates a good foundation that would allow existing and new code to get cleaner.
>>
>> Please, take a look at the change https://asterix-gerrit.ics.uci.edu/#/c/1728/ <https://asterix-gerrit.ics.uci.edu/#/c/1728/>
if interested and let me know if you have any comments. Note that it fails storage check test
and that is expected because it changes the persisted resource info classes.
>>
>> Cheers,
>> Abdullah.
>

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