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Posted to issues-all@impala.apache.org by "Wenzhe Zhou (Jira)" <ji...@apache.org> on 2023/10/16 23:11:00 UTC
[jira] [Comment Edited] (IMPALA-12501) Caching of JDBC drivers in local storage for external JDBC tables
[ https://issues.apache.org/jira/browse/IMPALA-12501?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17775947#comment-17775947 ]
Wenzhe Zhou edited comment on IMPALA-12501 at 10/16/23 11:10 PM:
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GenericJdbcDatabaseAccessor class provides cache for dbcp DataSource (see https://github.com/apache/impala/blob/master/java/ext-data-source/jdbc/src/main/java/org/apache/impala/extdatasource/jdbc/dao/GenericJdbcDatabaseAccessor.java#L66-L84). The jdbc driver don't need to be re-loaded if the dbcp DataSource object could be found in the cache (https://github.com/apache/impala/blob/master/java/ext-data-source/jdbc/src/main/java/org/apache/impala/extdatasource/jdbc/dao/GenericJdbcDatabaseAccessor.java#L226-L252). The caching is controlled by the table property of external JDBC data source table. If initString started with[ "CACHE_CLASS::"|https://github.com/apache/impala/blob/master/java/ext-data-source/jdbc/src/main/java/org/apache/impala/extdatasource/jdbc/JdbcDataSource.java#L88-L91], dbcp DataSource will NOT be cleaned when the GenericJdbcDatabaseAccessor object is closed.
Do we need another layer of cache ?
was (Author: wzhou):
GenericJdbcDatabaseAccessor class provides cache for dbcp DataSource (see https://github.com/apache/impala/blob/master/java/ext-data-source/jdbc/src/main/java/org/apache/impala/extdatasource/jdbc/dao/GenericJdbcDatabaseAccessor.java#L66-L84). The jdbc driver don't need to be re-loaded if the dbcp DataSource object could be found in the cache (https://github.com/apache/impala/blob/master/java/ext-data-source/jdbc/src/main/java/org/apache/impala/extdatasource/jdbc/dao/GenericJdbcDatabaseAccessor.java#L226-L252). The caching is controlled by the table property of external JDBC data source table. If initString started with "CACHE_CLASS::", dbcp DataSource will NOT be cleaned when the GenericJdbcDatabaseAccessor object is closed.
Do we need another layer of cache ?
> Caching of JDBC drivers in local storage for external JDBC tables
> -----------------------------------------------------------------
>
> Key: IMPALA-12501
> URL: https://issues.apache.org/jira/browse/IMPALA-12501
> Project: IMPALA
> Issue Type: Sub-task
> Components: Frontend
> Reporter: Wenzhe Zhou
> Assignee: Wenzhe Zhou
> Priority: Major
>
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