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https://issues.apache.org/jira/browse/HIVE-30218?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Raghav Aggarwal updated HIVE-30218:
-----------------------------------
Description:
Hive Metastore persistence consumers exclusively operate under the
**`READ_COMMITTED`** isolation level:
* **ACID / Transactional Layer (`TxnHandler`)**:
`TransactionContextManager` initializes every transaction with
`transactionDefinition.setIsolationLevel(Isolation.READ_COMMITTED.value())`.
* **Metadata / JDO Layer (`ObjectStore`)**: DataNucleus defaults to
`datanucleus.transactionIsolation = "read-committed"`.
However, `HikariCPDataSourceProvider` previously left the pool's default
transaction isolation unconfigured, deferring to the underlying database
engine's default. On
**MySQL and MariaDB**, the server and driver default to **`REPEATABLE
READ`**.
> Eliminate redundant transaction isolation round-trips in Metastore and
> upgrade HikariCP to 7.1.0
> ------------------------------------------------------------------------------------------------
>
> Key: HIVE-30218
> URL: https://issues.apache.org/jira/browse/HIVE-30218
> Project: Hive
> Issue Type: Improvement
> Reporter: Raghav Aggarwal
> Assignee: Raghav Aggarwal
> Priority: Major
>
> Hive Metastore persistence consumers exclusively operate under the
> **`READ_COMMITTED`** isolation level:
> * **ACID / Transactional Layer (`TxnHandler`)**:
> `TransactionContextManager` initializes every transaction with
>
> `transactionDefinition.setIsolationLevel(Isolation.READ_COMMITTED.value())`.
> * **Metadata / JDO Layer (`ObjectStore`)**: DataNucleus defaults to
> `datanucleus.transactionIsolation = "read-committed"`.
> However, `HikariCPDataSourceProvider` previously left the pool's default
> transaction isolation unconfigured, deferring to the underlying database
> engine's default. On
> **MySQL and MariaDB**, the server and driver default to **`REPEATABLE
> READ`**.
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