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From Siddharth Verma <verma.siddha...@snapdeal.com>
Subject Discrepancy while paging through table, and static column updated inbetween
Date Tue, 19 Apr 2016 15:25:31 GMT
Hi,

We are using cassandra(dsc3.0.3) on production.

For some purpose, we were doing a full table scan (setPagingState and
getPagingState used on ResultSet in java program), and there has been some
discrepancy when we ran the same job multiple times.
Each time some new data was added to the output, and some was left out.

Side Note 1 :
Table structure
col1, col2, col3, col4, col5, col6
Primary key(col1, col2)
col5 is static column
col6 static column. Used to explicitly store updated time when col5 changed


Sample Data
1,A,AA,AAA,STATIC,T1
1,B,BB,BBB,STATIC,T1
1,C,CC,CCC,STATIC,T1
1,D,DD,DDD,STATIC,T1

For some key, sometime col6 was updated while the job was running, so some
values were not printed for that partition key.

Side Note 2 :
we did -> select col6, writetime(col6) from ... where col1=... and col2=...
For the data that was missed out to make sure that particular entry wasn't
added later.


Side Note 3:
The above scenario that some col6 was updated while job was running,
therefore some entry for that partition key was ignored, is an assumption
from our end.
We can't understand why some entries were not printed in the table scan.

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