Jia Long Loh created ZEPPELIN-4201:
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Summary: JDBC documentation for common.max_rows not accurate
Key: ZEPPELIN-4201
URL: https://issues.apache.org/jira/browse/ZEPPELIN-4201
Project: Zeppelin
Issue Type: Bug
Components: documentation
Affects Versions: 0.8.1
Reporter: Jia Long Loh
In the documentation for
[0.8.1|https://zeppelin.apache.org/docs/latest/interpreter/jdbc.html], it is
stated that `common.max_count` is used to control the number of output rows
from the jdbc.
However, a recent change
[here|https://github.com/apache/zeppelin/commit/9f5cf17bdd09c400dc06679bbc61d381fa0a8c56#diff-ecdae8ee9594a5c4b21a3c217a3f130cR720]
to 0.8.1 has resulted in `setMaxRows` using the MAX_ROWS_KEY =
"zeppelin.jdbc.maxRows". Rows above 1000 seem to be silently dropped as per the
documentation
[here|https://docs.oracle.com/javase/8/docs/api/java/sql/Statement.html#setMaxRows-int-].
This is very misleading (and even quite dangerous), as many people would assume
that as per the documentation, it is common.max_count that controls the number
of rows, and because the other rows are silently dropped, this could result in
inaccurate results.
We should highlight in the documentation that zeppelin.jdbc.maxRows needs to be
set to control the number of rows the jdbc returns.
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