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Posted to notifications@shardingsphere.apache.org by GitBox <gi...@apache.org> on 2020/03/31 07:13:35 UTC
[GitHub] [incubator-shardingsphere] cherrylzhao opened a new pull request
#5016: refactor DatabaseMetaData for sharding-jdbc
cherrylzhao opened a new pull request #5016: refactor DatabaseMetaData for sharding-jdbc
URL: https://github.com/apache/incubator-shardingsphere/pull/5016
in sharding-jdbc getMetaData is like this:
```java
@Override
public DatabaseMetaData getMetaData() throws SQLException {
return getCachedConnections().isEmpty() ? runtimeContext.getCachedDatabaseMetaData() : getCachedConnections().values().iterator().next().getMetaData();
}
```
two problems exists:
- if `getCachedConnections().isEmpty()`, databaseMetaData will get from a physical connection, however physical connection's metadata will not return a logic tableName which we have converted in CachedDatabaseMetaData by ShardingRule currently.
- getCachedConnections().isNotEmpty, databaseMetaData will get from CachedDatabaseMetaData which get connection every time for ResultSet returned interface
I have extract a MultipleDatabaseMetaData abstract class which includes cacchedConnection, subclass is ShardingDatabaseMetaData and MasterSlaveDatabaseMetaData. CachedDatabaseMetaData will only contains cached properties only, initialized when DataSource was created. In this way below 2 problems will be resolved, meantime the performance will not reduce.
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[GitHub] [incubator-shardingsphere] terrymanu merged pull request #5016:
refactor DatabaseMetaData for sharding-jdbc
Posted by GitBox <gi...@apache.org>.
terrymanu merged pull request #5016: refactor DatabaseMetaData for sharding-jdbc
URL: https://github.com/apache/incubator-shardingsphere/pull/5016
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