Hello Marcel Kornacker,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/5710
to look at the new patch set (#5).
Change subject: IMPALA-4449: Revisit table locking pattern in the catalog
......................................................................
IMPALA-4449: Revisit table locking pattern in the catalog
This commit fixes an issue where multiple long-running operations on the
same catalog object (e.g. table) can block other catalog operations from
making progress.
Problem:
IMPALA-1480 introduced table level locking that in conjunction with the
global catalog lock ensures serialized access to catalog table objects.
In some cases (e.g. multiple long running operations on same table), the
locking pattern used resulted in the catalog lock being held for
a long period of time, thus blocking other catalog operations from making
any progress. That resulted in high response times and the system
appearing to be hung.
Solution:
Change the locking pattern in the catalog for protecting table objects
so that no operation will hold the catalog lock for a long time if it
fails to acquire a table lock. The operation that attempts to acquire a
table lock and fails to do so must release the catalog lock and retry.
The use of fair locks prevent starvation from happening. The only
operation that doesn't follow this retry logic is the
getCatalogObjects() call that retrieves a snapshot of the catalog
metadata for transmitting to the statestore.
Testing:
I manually tested this change by running concurrency tests using JMeter
and verified that the throughput of catalog operations on a specific table
is not affected by other concurrent long running operations (e.g. refresh)
on a different table.
Change-Id: Id08e21da31deb1f003b3cada4517651f3b3b2bb2
---
M fe/src/main/java/org/apache/impala/catalog/CatalogServiceCatalog.java
M fe/src/main/java/org/apache/impala/catalog/Table.java
M fe/src/main/java/org/apache/impala/service/CatalogOpExecutor.java
3 files changed, 183 insertions(+), 73 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/10/5710/5
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Id08e21da31deb1f003b3cada4517651f3b3b2bb2
Gerrit-PatchSet: 5
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Dimitris Tsirogiannis <dtsirogian...@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com>
Gerrit-Reviewer: Bharath Vissapragada <bhara...@cloudera.com>
Gerrit-Reviewer: Dan Hecht <dhe...@cloudera.com>
Gerrit-Reviewer: Dimitris Tsirogiannis <dtsirogian...@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <mar...@cloudera.com>
