Unclear configuration parameters of Persistent Store

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Unclear configuration parameters of Persistent Store

dmagda
Igniters,

I’ve been working on the documentation for the Persistent Store fixing Java Doc in parallel:
https://apacheignite.readme.io/v2.0/docs/distributed-persistent-store <https://apacheignite.readme.io/v2.0/docs/distributed-persistent-store>

However, there are several configuration parameters of PersistentStoreConfiguration that don’t make sense to me:
* PersistentStoreConfiguration.setLockWaitTime
* PersistentStoreConfiguration.setWalHistorySize
* PersistentStoreConfiguration.setWalArchivePath (here I can get what this "Full WAL segments will be copied to this directory before reuse.” means to me as to the end user)

Alex G., as the store architect, please document those methods so that the users can understand what are they for and when they should be used. Also it will be great if you look through the rest of the parameters.

Finally, I do remember there was a way to do the writes to the store in async or sync mode but I can’t find any parameter to tweak the behavior. Is there any other configuration API I’m not aware of?


Denis



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Re: Unclear configuration parameters of Persistent Store

dmagda
Alex G.,

> * PersistentStoreConfiguration.setWalHistorySize
> * PersistentStoreConfiguration.setWalArchivePath

I could figure out the goal of these two parameters below referring to the store architecture guide [1] and updated the Java docs.

> PersistentStoreConfiguration.setLockWaitTime

However, it’s still not obvious how to document this lockWaitTime. Plus, the checkpointing description in [1] confused me a bit. I assumed that the checkpointing is used to unwind the WAL only but know I see that it literally copies data from the memory to disk. What do we store in WAL then if it’s not a delta of an update?

In general, I would need your help to finalize the checkpoint section and update the WAL section in the high-level user documentation I’ve been working on:
https://apacheignite.readme.io/v2.0/docs/distributed-persistent-store

[1] https://cwiki.apache.org/confluence/display/IGNITE/Persistent+Store+Architecture#PersistentStoreArchitecture-Checkpointing


Denis

> On May 25, 2017, at 6:06 PM, Denis Magda <[hidden email]> wrote:
>
> Igniters,
>
> I’ve been working on the documentation for the Persistent Store fixing Java Doc in parallel:
> https://apacheignite.readme.io/v2.0/docs/distributed-persistent-store <https://apacheignite.readme.io/v2.0/docs/distributed-persistent-store>
>
> However, there are several configuration parameters of PersistentStoreConfiguration that don’t make sense to me:
> * PersistentStoreConfiguration.setLockWaitTime
> * PersistentStoreConfiguration.setWalHistorySize
> * PersistentStoreConfiguration.setWalArchivePath (here I can get what this "Full WAL segments will be copied to this directory before reuse.” means to me as to the end user)
>
> Alex G., as the store architect, please document those methods so that the users can understand what are they for and when they should be used. Also it will be great if you look through the rest of the parameters.
>
> Finally, I do remember there was a way to do the writes to the store in async or sync mode but I can’t find any parameter to tweak the behavior. Is there any other configuration API I’m not aware of?
>
> —
> Denis
>
>
>