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From Jens Deppe <jde...@pivotal.io>
Subject Re: [DISCUSS] easy string based partitioning
Date Mon, 05 Jun 2017 15:46:48 GMT
I like the idea of keeping the configuration 'conventional' and thus not
requiring any server configuration. As soon as you need to define a regex
on the server you might as well be writing PartitionResolver code.

As an aside I also think that using regexes to parse keys would also
introduce a measurable performance hit.

--Jens

On Mon, Jun 5, 2017 at 8:21 AM, Udo Kohlmeyer <ukohlmeyer@pivotal.io> wrote:

> Whilst I like the idea to make something (and yes,
> DelimitedStringPartitionResolver is the simplest), I feel that we might
> be able to do one better.
>
> */Could/* one possibly have an /*SPEL*/ <https://docs.spring.io/spring
> -framework/docs/current/spring-framework-reference/html/expressions.html>-based
> PartitionResolver for this? At least this way, we don't have to rely on
> delimiters or a strong knowledge of REGEX.
>
> IMO, this would provide the greatest bang for buck implementation.
>
> --Udo
>
>
>
>
> On 6/2/17 19:15, Jacob Barrett wrote:
>
>> If you implement as regular expression the user doesn't have to reformat
>> their key to a specific format (akin to making them implement a class). I
>> would concat the matching groups for generate the routing key.
>>
>> Consider RegEx: .*\bcorrelation=(\d+).*\bmaybe-something-else=(\w)
>> With Keys:
>> A: my,key;with:any-chars;unique=12345;correlation=678/and,maybe
>> -something-else=a
>> B: my,key;unique=876324;correlation=678;and,maybe-something-else=a,foo
>> C: somthing;different=988975;correlation=678;then,maybe-something-else=ba
>>
>> Keys A and B would have routing key '678a'. Key C would have routing key
>> '678b'.
>>
>> -Jake
>>
>>
>>
>> Consider
>>
>> On Fri, Jun 2, 2017 at 4:02 PM Darrel Schneider <dschneider@pivotal.io>
>> wrote:
>>
>> Geode partitioned regions usually partition the data based on the key's
>>> hashcode.
>>> You can do your own partitioning by implementing the PartitionResolver
>>> interface and configuring it on the partitioned region.
>>>
>>> In some use cases needing to deploy your class that implements
>>> PartitionResolver can be problematic so we would like to find a way to
>>> offer partitioning based on a portion of the key (instead of the default
>>> which uses the entire key) that does not require you to implement your
>>> own
>>> PartitionResolver and does not require you to deploy your own code to do
>>> the custom partitioning.
>>>
>>> Another group of users that do not want to implement PartitionResolver
>>> are
>>> non-java clients. So the solution is required to be usable by non-java
>>> geode clients without needing to reimplement the client to support a new
>>> feature.
>>>
>>> Another constraint on the solution is for it to be both easy to use and
>>> easy to implement.
>>>
>>> The proposed solution is to provide a class named:
>>>      org.apache.geode.cache.StringPrefixPartitionResolver
>>> This class will implement PartitionResolver and have a default
>>> constructor.
>>> To use it you need to configure a partitioned region's PartitionResolver
>>> using the already existing mechanism for this (api, gfsh, or xml).
>>> The StringPrefixPartitionResolver will require all keys on its region to
>>> be
>>> of type String.
>>> It also requires that the string key contains at least one ':' character.
>>> The substring of the key that precedes the first ':' is the prefix that
>>> will be returned from "getRoutingObject".
>>>
>>> An example of doing this in gfsh is:
>>>      create region --name=r1 --type=PARTITION
>>> --partition-resolver=org.apache.geode.cache.StringPrefixPart
>>> itionResolver
>>>
>>> Note that attempting to use a key that is not a String or does not
>>> contain
>>> a ':' will throw an exception. This is to help developers realize they
>>> made
>>> a mistake.
>>>
>>> Note that the delimiter is always a ':'. It would be easy to made the
>>> delimiter configurable when using apis or xml but currently gfsh does not
>>> provide a way to pass parameters to the --partition-resolver create
>>> region
>>> option.
>>>
>>> The only public api change this proposal makes is the new
>>> StringPrefixPartitionResolver class.
>>>
>>>
>

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