[KUDU-1869] Scans do not work with hybrid time disabled and snapshot reads enabled

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Won't Fix
• Affects Version/s: 1.2.0
• Component/s: consensus
• Labels: impala
• Environment: Centos 6.6; ; kudu 1.2.0-cdh5.10.0; revision 01748528baa06b78e04ce9a799cc60090a821162; build type RELEASE; ; 6 nodes, 5 tservers/impalads
• Target Version/s: 1.7.0
• Assignee: David Alves
• Reporter: Matthew Jacobs
• Created: 10/Feb/17 18:16
• Updated: 08/Mar/18 23:44
• Resolved: 08/Mar/18 23:44

Description

With -use_hybrid_clock=false and scanning with SNAPSHOT_READ, all scans appear to be timing out with the following error message:

[vc0736.halxg.cloudera.com:21000] > SELECT COUNT(*) FROM functional_kudu.alltypes;
Query: select COUNT(*) FROM functional_kudu.alltypes
Query submitted at: 2017-02-10 09:50:02 (Coordinator: http://vc0736.halxg.cloudera.com:25000)
Query progress can be monitored at: http://vc0736.halxg.cloudera.com:25000/query_plan?query_id=ff48eb0af82f057e:f2c1e2f800000000
WARNINGS: 
Unable to open scanner: Timed out: unable to retry before timeout: Remote error: Service unavailable: Timed out: could not wait for desired snapshot timestamp to be consistent: Timed out waiting for ts: L: 3632307 to be safe (mode: NON-LEADER). Current safe time: L: 3598991 Physical time difference: None (Logical clock): Remote error: Service unavailable: Timed out: could not wait for desired snapshot timestamp to be consistent: Timed out waiting for ts: L: 3625836 to be safe (mode: NON-LEADER). Current safe time: L: 3593993 Physical time difference: None (Logical clock)

This is a severe issue for Impala which aims to keep SNAPSHOT_READ enabled.

Issue Links

• is related to: KUDU-1704 Add a new read mode to perform bounded staleness snapshot reads