Hello Alexey Serbin, Kudu Jenkins, Andrew Wong, Grant Henke,
I'd like you to reexamine a change. Please visit
http://gerrit.cloudera.org:8080/17773
to look at the new patch set (#16).
Change subject: KUDU-1260: Fix prefetching bug on Java scanner
......................................................................
KUDU-1260: Fix prefetching bug on Java scanner
Add a UT to test prefetching. The UT has two concurrent threads: writing
thread and scanner thread. The writing thread records the timestamp of
its write, and the scanner thread creates two scanners (w and w/o prefetching),
by comparing the scan result of the two scanners, we can verify the
prefetching result.
When prefetching is enabled, there is a RowResultIterator prefetched and
it will override the one which has not yet been consumed in current
implementation, as a result, some data will loss. The fix is simple:
use an atomic reference to cache the result and avoid value overriding.
Furthermore, there are at most two concurrent ScanRequests
sent to the tserver. But if the scan data reached the end, only one
hasMore=false is returned.
As a result, one of the ScanRequests got "scanner not found (it may have
expired)" exception.
The same issue occurs for KeepAliveRequest. This patch also addressed this
issue.
Change-Id: I853a041d86c75ec196d7d4ff45af4673c5c5f5cd
---
M java/kudu-client/src/main/java/org/apache/kudu/client/AsyncKuduScanner.java
A
java/kudu-client/src/test/java/org/apache/kudu/client/TestKuduScannerPrefetching.java
2 files changed, 443 insertions(+), 35 deletions(-)
git pull ssh://gerrit.cloudera.org:29418/kudu refs/changes/73/17773/16
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Gerrit-Project: kudu
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I853a041d86c75ec196d7d4ff45af4673c5c5f5cd
Gerrit-Change-Number: 17773
Gerrit-PatchSet: 16
Gerrit-Owner: Hongjiang Zhang <[email protected]>
Gerrit-Reviewer: Alexey Serbin <[email protected]>
Gerrit-Reviewer: Andrew Wong <[email protected]>
Gerrit-Reviewer: Grant Henke <[email protected]>
Gerrit-Reviewer: Hongjiang Zhang <[email protected]>
Gerrit-Reviewer: Kudu Jenkins (120)
