[HBASE-15235] Inconsistent cell reads over multiple bulk-loaded HFiles

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Assignee: Apekshit Sharma
• Reporter: Apekshit Sharma
• Created: 08/Feb/16 23:51
• Updated: 09/Feb/16 03:33
• Resolved: 09/Feb/16 03:33

Description

If there are two bulkloaded hfiles in a region with same seqID and duplicate keys*, get and scan may return different values for a key.
More details:

• one of the rows had 200k+ columns. say row is 'r', column family is 'cf' and column qualifiers are 1 to 1000.
• hfiles were split somewhere along that row, but there were a range of columns in both hfiles. For eg, something like - hfile1: ["", r:cf:70) and hfile2: [r:cf:40, ....).
• Between columns 40 to 70, some (not all) columns were in both the files with different values. Whereas other were only in one of the files.

In such a case, depending on file size (because we take it into account when sorting hfiles internally), we may get different values for the same cell (say "r", "cf:50") depending on what we call: get "r" "cf:50" or get "r" "cf:".

I have been able to replicate this issue, will post the instructions shortly.

• not sure how this would happen. These files are small ~50M, nor could i find any setting for max file size that could lead to splits. Need to investigate more.

Issue Links

• duplicates: HBASE-15236 Inconsistent cell reads over multiple bulk-loaded HFiles