[IMPALA-8968] Fix self-event detection on database events.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: Impala 3.4.0
• Component/s: Frontend
• Epic Color: ghx-label-3
• Assignee: Anurag Mantripragada
• Reporter: Anurag Mantripragada
• Created: 23/Sep/19 23:18
• Updated: 18/Dec/20 08:33
• Resolved: 18/Dec/20 08:33

Description

When event processing is turned on, self-events are not detected for DATABASE level events (create/alter/drop database). Reproduced using the below statements:

CREATE DATABASE test;

CREATE FUNCTION test.fn_test (INT, STRING) RETURNS BOOLEAN LOCATION '/test-warehouse/dummy.jar' SYMBOL='com.cloudera.impala.TestUdf';

DROP FUNCTION test.fn_test(INT, STRING);

DROP DATABASE test CASCADE; 

Since the events processor could not detect self-events, it will try to process the ALTER_DATABASE event created by dropping the function. However, it doesn't find the DB and errors out like below:

I0923 16:09:46.042317  6727 MetastoreEventsProcessor.java:480] Received 2 events. Start event id : 30077
I0923 16:09:46.042317  6727 MetastoreEventsProcessor.java:480] Received 2 events. Start event id : 30077
I0923 16:09:46.042853  6727 MetastoreEvents.java:382] EventId: 30078 EventType: ALTER_DATABASE Creating event 30078 of type ALTER_DATABASE on database test
I0923 16:09:46.044441  6727 MetastoreEvents.java:382] EventId: 30079 EventType: DROP_DATABASE Creating event 30079 of type DROP_DATABASE on database test
I0923 16:09:46.050657  6727 MetastoreEvents.java:231] Total number of events received: 2 Total number of events filtered out: 0
I0923 16:09:46.051167  6727 MetastoreEvents.java:382] EventId: 30078 EventType: ALTER_DATABASE Received exception Database test not found. Ignoring self-event evaluation
E0923 16:09:46.056273  6727 MetastoreEventsProcessor.java:525] Unexpected exception received while processing event
Java exception follows:org.apache.impala.catalog.events.MetastoreNotificationException: Unable to process event 30078 of type ALTER_DATABASE. Event processing will be stopped.
 at org.apache.impala.catalog.events.MetastoreEventsProcessor.processEvents(MetastoreEventsProcessor.java:614)
 at org.apache.impala.catalog.events.MetastoreEventsProcessor.processEvents(MetastoreEventsProcessor.java:511)
 at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
 at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
 at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
 at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
 at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.impala.catalog.DatabaseNotFoundException: Database test not found
 at org.apache.impala.catalog.CatalogServiceCatalog.updateDb(CatalogServiceCatalog.java:1060)
 at org.apache.impala.catalog.events.MetastoreEvents$AlterDatabaseEvent.process(MetastoreEvents.java:1225)
 at org.apache.impala.catalog.events.MetastoreEvents$MetastoreEvent.processIfEnabled(MetastoreEvents.java:316)
 at org.apache.impala.catalog.events.MetastoreEventsProcessor.processEvents(MetastoreEventsProcessor.java:609)
 ... 8 more
E0923 16:09:46.056489  6727 MetastoreEventsProcessor.java:631] Notification event is null
W0923 16:09:56.057376  6727 MetastoreEventsProcessor.java:504] Event processing is skipped since status is ERROR. Last synced event id is 30077