Introduce row_limit param

[varun-edachali-dbx]

What type of PR is this?

• Feature

Description

Introduces a row_limit param in the Cursor that constrains the number of rows in the query result, through resultRowLimit in Thrift and through max_rows in SEA.

Despite row_limit not existing in the spec, we feel it is reasonable to introduce it as a param in the Cursor, because:

• the Connection class has a number of non-spec params
• a risk of non-spec methods is the feature not being discovered (i.e., users not realising this param is available to them), but this is not a major issue, since the feature can effectively be replicated by including LIMIT in their SQL query.

How is this tested?

• Unit tests
• E2E Tests
• Manually
• N/A

Related Tickets & Documents

N/A

[jayantsing-db]

is this a breaking change in thrift? the thrift users would have to change to row_limit?

[varun-edachali-dbx]

is this a breaking change in thrift? the thrift users would have to change to row_limit?

There is currently no way for the user to specify a row limit with the Thrift backend. The newly introduced row_limit will set resultRowLimit in TExecuteStatementReq and allow the user to do so. It is not a breaking change because this defaults to None, which would maintain current behaviour.

In the current implementation, arraysize is set as the max_rows for direct results in case of Thrift. It does not constrain the total rows in the result. row_limit and arraysize will serve distinct purposes.