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https://issues.apache.org/jira/browse/HBASE-5121?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13181791#comment-13181791
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Zhihong Yu commented on HBASE-5121:
-----------------------------------
w.r.t. introducing new exception, here is StoreScanner.next():
{code}
* @return true if there are more rows, false if scanner is done
*/
@Override
public synchronized boolean next(List<KeyValue> outResult, int limit) throws
IOException {
checkReseek();
{code}
The return value has clear meaning. One approach is to change return type to an
enum.
@Chunhui:
Do you have time to come up with a patch that doesn't rely on new exception.
Instead, it relies on StoreScanner.next() returning an enum (SCAN_DONE,
MORE_ROWS, PEEK_CHANGED).
This way, people can evaluate both approaches.
Of course, Stack and Todd may comment on other areas of the patch.
> MajorCompaction may affect scan's correctness
> ---------------------------------------------
>
> Key: HBASE-5121
> URL: https://issues.apache.org/jira/browse/HBASE-5121
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.90.4
> Reporter: chunhui shen
> Assignee: chunhui shen
> Priority: Critical
> Fix For: 0.94.0, 0.92.1, 0.90.6
>
> Attachments: 5121-trunk-combined.txt, 5121.90,
> hbase-5121-testcase.patch, hbase-5121.patch, hbase-5121v2.patch
>
>
> In our test, there are two families' keyvalue for one row.
> But we could find a infrequent problem when doing scan's next if
> majorCompaction happens concurrently.
> In the client's two continuous doing scan.next():
> 1.First time, scan's next returns the result where family A is null.
> 2.Second time, scan's next returns the result where family B is null.
> The two next()'s result have the same row.
> If there are more families, I think the scenario will be more strange...
> We find the reason is that storescanner.peek() is changed after
> majorCompaction if there are delete type KeyValue.
> This change causes the PriorityQueue<KeyValueScanner> of RegionScanner's heap
> is not sure to be sorted.
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