Tanuj Khurana created PHOENIX-8006:
--------------------------------------
Summary: Ungrouped aggregate queries serialize on the client when
server paging returns partial results
Key: PHOENIX-8006
URL: https://issues.apache.org/jira/browse/PHOENIX-8006
Project: Phoenix
Issue Type: Bug
Affects Versions: 5.3.2, 5.3.1, 5.2.2
Reporter: Tanuj Khurana
Assignee: Tanuj Khurana
Attachments: ungrouped-aggregate-serial-drain-repro.patch,
ungrouped-aggregate-serial-drain-rpc-trace-evidence.txt
For an ungrouped aggregate query (e.g. SELECT COUNT(*) FROM t WHERE ...)
executed with scanner lease renewal enabled (the default,
phoenix.scanner.lease.renew.enabled=true), the per-region scan results are
drained serially on the client caller thread whenever the server cannot
complete a region's aggregation within a single page-time budget. Instead of
the regions being scanned concurrently, the query degrades to one client RPC
per scanned page, summed sequentially across all regions. On large tables this
turns a query that should complete in tens of seconds into one that can take
many minutes.
All ungrouped aggregate queries (no GROUP BY) — COUNT/SUM/MIN/MAX/AVG,
COUNT(DISTINCT ...) are affected.
Repro
{code:java}
# Turn trace logging phoenix-core/src/test/resources/log4j2-test.properties
logger.rpc.name = org.apache.hadoop.hbase.ipc.AbstractRpcClient
logger.rpc.level = TRACE {code}
Test in ServerPagingIT
[^ungrouped-aggregate-serial-drain-repro.patch]
Serial Execution output
[^ungrouped-aggregate-serial-drain-rpc-trace-evidence.txt]
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
