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https://issues.apache.org/jira/browse/HBASE-16876?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15602200#comment-15602200
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Neal Young commented on HBASE-16876:
------------------------------------
I'd be more comfortable if the patch were vetted first by someone who is more
familiar with the specification of the ratio-based compaction policy, and the
code that calls it, that sets mayBeStuck. Or if I were to submit the patch,
would it be so vetted then?
> RatioBasedCompactionPolicy ignores mayBeStuck
> ---------------------------------------------
>
> Key: HBASE-16876
> URL: https://issues.apache.org/jira/browse/HBASE-16876
> Project: HBase
> Issue Type: Bug
> Components: Compaction
> Reporter: Neal Young
> Labels: newbie
>
> I'm a newbie so may not be reporting this bug correctly. The bug currently
> shows in lines 181 - 190 here :
> http://hbase.apache.org/xref/org/apache/hadoop/hbase/regionserver/compactions/RatioBasedCompactionPolicy.html#181
> .
> {code:title=Bar.java|borderStyle=solid}
> 176 while (countOfFiles - start >= comConf.getMinFilesToCompact() &&
> 177 fileSizes[start] > Math.max(comConf.getMinCompactSize(),
> 178 (long) (sumSize[start + 1] * ratio))) {
> 179 ++start;
> 180 }
> 181 if (start < countOfFiles) {
> 182 LOG.info("Default compaction algorithm has selected " +
> (countOfFiles - start)
> 183 + " files from " + countOfFiles + " candidates");
> 184 } else if (mayBeStuck) {
> 185 // We may be stuck. Compact the latest files if we can.
> 186 int filesToLeave = candidates.size() -
> comConf.getMinFilesToCompact();
> 187 if (filesToLeave >= 0) {
> 188 start = filesToLeave;
> 189 }
> 190 }
> {code}
> On reaching line 176, start = 0. When comConf.getMinFilesToCompact() is at
> least 2 (as occurs in the default), the while loop is guaranteed to terminate
> with start < countOfFiles. Hence, the else clause starting at line 184 never
> executes, regardless of the value of mayBeStuck.
> Perhaps the following code would be better, but I'm not sure:
> {code:title=Bar.java|borderStyle=solid}
> while (start < countOfFiles
> && fileSizes[start] > Math.max(comConf.getMinCompactSize(),
> (long) (sumSize[start + 1] *
> ratio))) {
> ++start;
> }
> if (countOfFiles - start < comConf.getMinFilesToCompact()) {
> if (mayBeStuck && countOfFiles >= comConf.getMinFilesToCompact()) {
> start = countOfFiles - comConf.getMinFilesToCompact();
> } else {
> start = countOfFiles;
> }
> }
> if (countOfFiles - start > 0) {
> LOG.info("Default compaction algorithm has selected " + (countOfFiles
> - start)
> + " files from " + countOfFiles + " candidates");
> }
> {code}
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