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Posted to issues@hbase.apache.org by "Anoop Sam John (JIRA)" <ji...@apache.org> on 2016/07/01 07:41:11 UTC
[jira] [Created] (HBASE-16162) Unnecessary push active segments to
pipeline
Anoop Sam John created HBASE-16162:
--------------------------------------
Summary: Unnecessary push active segments to pipeline
Key: HBASE-16162
URL: https://issues.apache.org/jira/browse/HBASE-16162
Project: HBase
Issue Type: Sub-task
Reporter: Anoop Sam John
Assignee: Anoop Sam John
We have flow like this
{code}
protected void checkActiveSize() {
if (shouldFlushInMemory()) {
InMemoryFlushRunnable runnable = new InMemoryFlushRunnable();
}
getPool().execute(runnable);
}
}
private boolean shouldFlushInMemory() {
if(getActive().getSize() > inmemoryFlushSize) {
// size above flush threshold
return (allowCompaction.get() && !inMemoryFlushInProgress.get());
}
return false;
}
void flushInMemory() throws IOException {
// Phase I: Update the pipeline
getRegionServices().blockUpdates();
try {
MutableSegment active = getActive();
pushActiveToPipeline(active);
} finally {
getRegionServices().unblockUpdates();
}
// Phase II: Compact the pipeline
try {
if (allowCompaction.get() && inMemoryFlushInProgress.compareAndSet(false, true)) {
// setting the inMemoryFlushInProgress flag again for the case this method is invoked
// directly (only in tests) in the common path setting from true to true is idempotent
// Speculative compaction execution, may be interrupted if flush is forced while
// compaction is in progress
compactor.startCompaction();
}
{code}
So every write of cell will produce the check checkActiveSize(). When we are at border of in mem flush, many threads doing writes to this memstore can get this check to pass. Yes the AtomicBoolean is still false only. It is turned ON after some time once the new thread is started run and it push the active to pipeline etc.
So all these threads can push the same active to pipeline. We unnecessarily passing through same segment many times.
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