Connection Pushdown Processing¶

Data from JDBC data sources can be queried in the same way as other data sources. When querying using SQL tools, policy enforcement happens using the proxy pushdown enforcement mechanism to ensure optimum performance. For advanced concepts such as in-line SQL views, see Advanced Querying of JDBC Data Sources.

Predicate Pushdown¶

By default, Okera pushes down predicates for JDBC-backed data sources. To disable predicate pushdown for a particular JDBC-backed database or table, specify 'jdbc.predicates.pushdown.enabled' = 'false' in the DBPROPERTIES or TBLPROPERTIES.

Enable Proxy Pushdown Mode¶

To enable proxy pushdown mode for a connection, use the following Okera configuration parameters in the Okera configuration file.

PRESTO_ENABLE_PROXY: Use this configuration parameter to enable proxy mode. Valid values are true and false. To enable proxy mode, set this configuration parameter to true (the default).
PRESTO_PROXY_JDBC_PUSHDOWN: Use this configuration parameter to enable pushdown processing for JDBC-based connections. Valid values are true and false. To enable pushdown processing, set this configuration parameter to true (the default).
OKERA_CTE_REWRITE_ENABLED_ENGINES: Use this configuration parameter to indicate which Okera connection types should use proxy pushdown processing. Use commas to separate values. Valid values are awsathena, bigquery, dremio:direct, postgresql, redshift, and snowflake. For example:
```
OKERA_CTE_REWRITE_ENABLED_ENGINES: awsathena,bigquery,postresql
```
There are no defaults.
PRESTO_PROXY_DEBUG_ENABLED: Use this configuration parameter to enable proxy debugging. Valid values are true and false. The default is true.