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https://issues.apache.org/jira/browse/PHOENIX-3152?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Sergey Soldatov updated PHOENIX-3152:
-------------------------------------
Attachment: PHOENIX-3152.patch
Patch is quite simple. For any decision related to indexes I've added check
that the second plan is not the same type (if they are, we will consider them
as equal, i.e. return 0)
> Incorrect comparator in QueryOptimizer may cause IllegalArgumentException
> -------------------------------------------------------------------------
>
> Key: PHOENIX-3152
> URL: https://issues.apache.org/jira/browse/PHOENIX-3152
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.8.0
> Reporter: Sergey Soldatov
> Attachments: PHOENIX-3152.patch, PHOENIX-3152.sql
>
>
> The problem code is in QueryOptimizer#orderPlansBestToWorst
> When we have a lot of local similar indexes, all of them comes to the array
> of best candidates. After that we try to sort them using our own Comparator.
> In the compare we check first:
> 1. bound pk columns count
> 2. groupBy order
> 3. number of columns
> for two local indexes on different columns first 3 steps always passed (since
> they are equal)
> And now we execute the following checks:
> {noformat}
> // If all things are equal, don't choose local index as it
> forces scan
> // on every region (unless there's no start/stop key)
> if (table1.getIndexType() == IndexType.LOCAL) {
> return
> plan1.getContext().getScanRanges().getRanges().isEmpty() ? -1 : 1;
> }
> if (table2.getIndexType() == IndexType.LOCAL) {
> return
> plan2.getContext().getScanRanges().getRanges().isEmpty() ? 1 : -1;
> }
> {noformat}
> obvious that for similar two plans with similar scan ranges {{compare
> (plan1, plan2)}} and {{compare(plan2, plan1)}} will return the same result (1
> if ranges are not empty, -1 otherwise). This may cause following exception
> from {{Collections.sort}} :
> {noformat}
> at java.util.TimSort.mergeLo(TimSort.java:777)
> at java.util.TimSort.mergeAt(TimSort.java:514)Listening for transport
> at java.util.TimSort.mergeCollapse(TimSort.java:441)
> at java.util.TimSort.sort(TimSort.java:245)
> at java.util.Arrays.sort(Arrays.java:1512)
> at java.util.ArrayList.sort(ArrayList.java:1454)
> at java.util.Collections.sort(Collections.java:175)
> {noformat}
> I would suggest to add a check that if both plans are local indexes, then
> consider them equal, otherwise execute the check. [~jamestaylor],
> [~ram_krish] any thoughts?
> [[email protected]] FYI
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