Add support for TopN pushdown for Oracle #26688
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Older versions of Oracle (i.e. v11) support only WHERE ROWNUM <= number syntax, not FETCH FIRST number ROWS ONLY. So we wrapped the statement similar to the approach already used for LIMIT support: "SELECT * FROM (%s ORDER BY %s) WHERE ROWNUM <= %s". Oracle sets NULL values last by default. Sometimes, however, the default does not work, so we used explicit flag for nulls. Modified the topn related table names in BaseJdbcConnectorTest to shorter names, as Oracle's older version (i.e. v11) has a limit of 30 characters.
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Add support for TopN pushdown for Oracle
Description
Older versions of Oracle (i.e. v11) support only WHERE ROWNUM <= number syntax, not FETCH FIRST number ROWS ONLY. So we wrapped the statement similar to the approach already used for LIMIT support: "SELECT * FROM (%s ORDER BY %s) WHERE ROWNUM <= %s".
Oracle sets NULL values last by default. Sometimes, however, the default does not work, so we used explicit flag for nulls.
Modified the topn related table names in BaseJdbcConnectorTest to shorter names, as Oracle's older version (i.e. v11) has a limit of 30 characters.
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