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It is a follow-up jira/commit to IMPALA-12709. IMPALA-12152 and
IMPALA-12785 are affected when hierarchical metastore event
processing feature is enabled.
Following changes are incorporated with this patch:
1. Added creationTime_ and dispatchTime_ fields in MetastoreEvent
class to store the current time in millisec. They are used to
calculate:
a) Event dispatch time(time between a MetastoreEvent object
creation and when event is moved to inProgressLog_ of
EventExecutorService after dispatching it to a
DbEventExecutor).
b) Event schedule delays incurred at DbEventExecutors and
TableEventExecutors(time between an event moved to
EventExecutorService's inProgressLog_ and before start of
processing event at appropriate DbEventExecutor and
TableEventExecutor).
c) Event process time from EventExecutorService point of
view(time spent in inProgressLog_ before it is moved to
processedLog_).
Logs are added to show the event dispatch time, schedule
delays, process time from EventExecutorService point of
view for each event. Also a log is added to show the time
taken for event's processIfEnabled().
2. Added isDelimiter_ field in MetastoreEvent class to indicate
whether it is a delimiter event. It is set only when
hierarchical event processing is enabled. Delimiter is a kind
of metastore event that do not require event processing.
Delimeter event can be:
a) A CommitTxnEvent that do not have any write event info for
a given transaction.
b) An AbortTxnEvent that do not have write ids for a given
transaction.
c) An IgnoredEvent.
An event is determined and marked as delimiter in
EventExecutorService#dispatch(). They are not queued to a
DbEventExecutor for processing. They are just maintained in
the inProgressLog_ to preserve continuity and correctness in
synchronization tracking. The delimiter events are removed from
inProgressLog_ when their preceding non-delimiter metastore
event is removed from inProgressLog_.
3. Greatest synced event id is computed based on the dispatched
events(inProgressLog_) and processed events(processedLog_) tree
maps. Greatest synced event is the latest event such that all
events with id less than or equal to the latest event are
definitely synced.
4. Lag is calculated as difference between latest event time on HMS
and the greatest synced event time. It is shown in the log.
5. Greatest synced event id is used in IMPALA-12152 changes. When
greatest synced event id becomes greater than or equal to
waitForEventId, all the required events are definitely synced.
6. Event processor is paused gracefully when paused with command in
IMPALA-12785. This ensures that all the fetched events from HMS in
current batch are processed before the event processor is fully
paused. It is necessary to process the current batch of events
because, certain events like AllocWriteIdEvent, AbortTxnEvent and
CommitTxnEvent update table write ids in catalog upon metastore
event object creation. And the table write ids are later updated
to appropriate table object during their event process. Can lead
to inconsistent state of write ids on table objects when paused
abruptly in the middle of current batch of event processing.
7. Added greatest synced event id and event time in events processor
metrics. And updated description of lag, pending events, last
synced event id and event time metrics.
8. Atomically update the event queue and increment outstanding event
count in enqueue methods of both DbProcessor and TableProcessor
so that respective process methods do not process the event until
event is added to queue and outstanding event count is incremented.
Otherwise, event can get processed, outstanding event count gets
decremented before it is incremented in enqueue method.
9. Refactored DbEventExecutor, DbProcessor, TableEventExecutor and
TableProcessor classes to propapage the exception occurred along
with event during event processing. EventProcessException is a
wrapper added to hold reference to event being processed and
exception occurred.
10.Added AcidTableWriteInfo helper class to store table, writeids
and partitions for the transaction id received in CommitTxnEvent.
Testing:
- Added new tests and executed existing end to end tests.
- Have executed the existing tests with hierarchical event processing
enabled.
Change-Id: I26240f36aaf85125428dc39a66a2a1e4d3197e85
Reviewed-on: http://gerrit.cloudera.org:8080/22997
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Reviewed-by: Quanlong Huang <huangquanlong@gmail.com>