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https://issues.apache.org/jira/browse/HBASE-4485?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13152413#comment-13152413
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jirapos...@reviews.apache.org commented on HBASE-4485:
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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/2481/
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(Updated 2011-11-17 22:43:10.296972)
Review request for Ted Yu, Michael Stack, Jonathan Gray, Lars Hofhansl,
Amitanand Aiyer, Kannan Muthukkaruppan, Karthik Ranganathan, and Nicolas
Spiegelberg.
Changes
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added comments, based on kannan/nicolas' comments on the 89 branch.
Summary
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Part of the 2856 diff split into 3 parts for easier review
The first part is v6 of the patch submitted to:
https://reviews.apache.org/r/2224/
This is the fix for HBase-4485
This addresses bug hbase-4485.
https://issues.apache.org/jira/browse/hbase-4485
Diffs (updated)
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src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java 34263e4
src/main/java/org/apache/hadoop/hbase/regionserver/Store.java 7761c42
src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java f5b5c4c
Diff: https://reviews.apache.org/r/2481/diff
Testing
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running mvn test with all 3 patches together.
Thanks,
Amitanand
> Eliminate window of missing Data
> --------------------------------
>
> Key: HBASE-4485
> URL: https://issues.apache.org/jira/browse/HBASE-4485
> Project: HBase
> Issue Type: Sub-task
> Reporter: Amitanand Aiyer
> Assignee: Amitanand Aiyer
> Fix For: 0.94.0
>
> Attachments: 4485-v1.diff, 4485-v2.diff, 4485-v3.diff, 4485-v4.diff,
> repro_bug-4485.diff
>
>
> After incorporating v11 of the 2856 fix, we discovered that we are still
> having some ACID violations.
> This time, however, the problem is not about including "newer" updates; but,
> about missing older updates
> that should be including.
> Here is what seems to be happening.
> There is a race condition in the StoreScanner.getScanners()
> private List<KeyValueScanner> getScanners(Scan scan,
> final NavigableSet<byte[]> columns) throws IOException {
> // First the store file scanners
> List<StoreFileScanner> sfScanners = StoreFileScanner
> .getScannersForStoreFiles(store.getStorefiles(), cacheBlocks,
> isGet, false);
> List<KeyValueScanner> scanners =
> new ArrayList<KeyValueScanner>(sfScanners.size()+1);
> // include only those scan files which pass all filters
> for (StoreFileScanner sfs : sfScanners) {
> if (sfs.shouldSeek(scan, columns)) {
> scanners.add(sfs);
> }
> }
> // Then the memstore scanners
> if (this.store.memstore.shouldSeek(scan)) {
> scanners.addAll(this.store.memstore.getScanners());
> }
> return scanners;
> }
> If for example there is a call to Store.updateStorefiles() that happens
> between
> the store.getStorefiles() and this.store.memstore.getScanners(); then
> it is possible that there was a new HFile created, that is not seen by the
> StoreScanner, and the data is not present in the Memstore.snapshot either.
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