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Posted to issues@hbase.apache.org by "Appy (JIRA)" <ji...@apache.org> on 2016/02/09 05:48:18 UTC

[jira] [Updated] (HBASE-15236) Inconsistent cell reads over multiple bulk-loaded HFiles

     [ https://issues.apache.org/jira/browse/HBASE-15236?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Appy updated HBASE-15236:
-------------------------
    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.

  was:
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.


> Inconsistent cell reads over multiple bulk-loaded HFiles
> --------------------------------------------------------
>
>                 Key: HBASE-15236
>                 URL: https://issues.apache.org/jira/browse/HBASE-15236
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Appy
>            Assignee: Appy
>
> 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.



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