Luo Chen has posted comments on this change.

Change subject: Implemented Disk Components Alignment Based on IDs
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Patch Set 7:

(1 comment)

https://asterix-gerrit.ics.uci.edu/#/c/1761/6/asterixdb/asterix-common/src/main/java/org/apache/asterix/common/context/CorrelatedPrefixMergePolicy.java
File 
asterixdb/asterix-common/src/main/java/org/apache/asterix/common/context/CorrelatedPrefixMergePolicy.java:

PS6, Line 103: isMergeLagging(
> That should be fine because the merge policy should always checks the prima
I see. Then it makes sense.

However, this still wouldn't fully solve the problem for the following reason. 
Let say after the 10 disk components are added to both indexes, the policy 
schedules a merge operation for the primary index, but misses the secondary 
index since it's still being merged. After the secondary index finishes it's 
merge operation, it would have more disk components than the merge policy 
tolerates. However, even suppose the secondary index could trigger the merge 
policy, since the merge policy only looks at the primary index, it still won't 
schedule the merge operation since the disk components of the primary index do 
not need to be merged now. Still, we would wait until the next flush operation 
for the primary index.

This problem can be solved by let the merging policy (triggered at primary 
index) to wait for all secondary indexes to finish the ongoing merge 
operations. If that's the case, all indexes would be merged together, and no 
one would be left behind. But even for the current solution (without 
synchronization for merging but with flow control), this should be acceptable 
since the secondary index (more precisely, the inverted index) would at most 
miss one round of merge request.


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Gerrit-MessageType: comment
Gerrit-Change-Id: I768ee9ac0a8d3c99c631086093a6b778b2e7588e
Gerrit-PatchSet: 7
Gerrit-Project: asterixdb
Gerrit-Branch: master
Gerrit-Owner: Luo Chen <[email protected]>
Gerrit-Reviewer: Ian Maxon <[email protected]>
Gerrit-Reviewer: Jenkins <[email protected]>
Gerrit-Reviewer: Jianfeng Jia <[email protected]>
Gerrit-Reviewer: Luo Chen <[email protected]>
Gerrit-Reviewer: Till Westmann <[email protected]>
Gerrit-Reviewer: Yingyi Bu <[email protected]>
Gerrit-Reviewer: abdullah alamoudi <[email protected]>
Gerrit-HasComments: Yes

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