Murtadha Hubail has posted comments on this change.

Change subject: Allow lazy loading for persistent local resources
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Patch Set 5:

(2 comments)

https://asterix-gerrit.ics.uci.edu/#/c/344/5/asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/resource/PersistentLocalResourceRepository.java
File 
asterix-transactions/src/main/java/edu/uci/ics/asterix/transaction/management/resource/PersistentLocalResourceRepository.java:

Line 205:     public HashMap<Long, LocalResource> loadAndGetAllResources() 
throws HyracksDataException {
> In my opinion, a disk-access-transparent ResourceCache would serve the same
During recovery, the only piece of information that you have from the log is 
the resource id. You wouldn't know where to look to begin with. Also, while the 
system is recovering, all the memory is dedicated for that. There are no 
concurrent operations. So the memory issue isn't likely to happen.


Line 205:     public HashMap<Long, LocalResource> loadAndGetAllResources() 
throws HyracksDataException {
> Is it possible to have yet-another resourcesCache for that maps an ID to th
Yes, we would have to persist a new file at the root of every IO Device and 
load these files gradually during recovery until the required resource is 
found. Another option is to store a file per resource in a common location and 
make each file name to be the resource id. Then from that common location, you 
would get where the actual resource is.

As I mentioned, I don't think this is going to be an issue during recovery, and 
when it does, we could make loading the resources to the cache gradual which 
will make the recovery slower, but limit the amount of memory used.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I48b9260a3280750145f6ddb3783673a299055910
Gerrit-PatchSet: 5
Gerrit-Project: asterixdb
Gerrit-Branch: master
Gerrit-Owner: Murtadha Hubail <[email protected]>
Gerrit-Reviewer: Ian Maxon <[email protected]>
Gerrit-Reviewer: Jenkins <[email protected]>
Gerrit-Reviewer: Murtadha Hubail <[email protected]>
Gerrit-Reviewer: Yingyi Bu <[email protected]>
Gerrit-Reviewer: Yingyi Bu <[email protected]>
Gerrit-Reviewer: Young-Seok Kim <[email protected]>
Gerrit-Reviewer: abdullah alamoudi <[email protected]>
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