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Posted to dev@phoenix.apache.org by "Loknath Priyatham Teja Singamsetty (JIRA)" <ji...@apache.org> on 2016/08/04 17:55:20 UTC
[jira] [Resolved] (PHOENIX-3083) Avoid additional handling of
concurrency control inside timertask of BuildIndexScheduleTask when
ScheduledThreadPoolExecutor executeAtFixedRate does it internally
[ https://issues.apache.org/jira/browse/PHOENIX-3083?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Loknath Priyatham Teja Singamsetty resolved PHOENIX-3083.
----------------------------------------------------------
Resolution: Invalid
It is always safe and better to have concurrency control at the TimerTask run(), instead of relying on ScheduledThreadPoolExecutor.
> Avoid additional handling of concurrency control inside timertask of BuildIndexScheduleTask when ScheduledThreadPoolExecutor executeAtFixedRate does it internally
> ------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: PHOENIX-3083
> URL: https://issues.apache.org/jira/browse/PHOENIX-3083
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 4.8.0, 4.8.1
> Reporter: Loknath Priyatham Teja Singamsetty
> Assignee: Loknath Priyatham Teja Singamsetty
> Priority: Trivial
>
> MetaDataRegionObserver codesnippet where inprogress AtomicInteger is used for concurrency control:
> -----------------------------------------------------------------
> /**
> * Task runs periodically to build indexes whose INDEX_NEED_PARTIALLY_REBUILD is set true
> *
> */
> public static class BuildIndexScheduleTask extends TimerTask {
> // inProgress is to prevent timer from invoking a new task while previous one is still
> // running
> private final static AtomicInteger inProgress = new AtomicInteger(0);
> RegionCoprocessorEnvironment env;
> public BuildIndexScheduleTask(RegionCoprocessorEnvironment env) {
> this.env = env;
> }
> @Override
> public void run() {
> // FIXME: we should replay the data table Put, as doing a partial index build would only add
> // the new rows and not delete the previous index value. Also, we should restrict the scan
> // to only data within this region (as otherwise *every* region will be running this code
> // separately, all updating the same data.
> RegionScanner scanner = null;
> PhoenixConnection conn = null;
> if (inProgress.get() > 0) {
> LOG.debug("New ScheduledBuildIndexTask skipped as there is already one running");
> return;
> }
> try {
> inProgress.incrementAndGet();
> ----------------------------------------------------
> JAVADOC:
> --------------
> public ScheduledFuture<?> scheduleAtFixedRate(Runnable command,
> long initialDelay,
> long period,
> TimeUnit unit)
> Description copied from interface: ScheduledExecutorService
> Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of the task encounters an exception, subsequent executions are suppressed. Otherwise, the task will only terminate via cancellation or termination of the executor. If any execution of this task takes longer than its period, then subsequent executions may start late, but will not concurrently execute.
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