[HBASE-6580] Deprecate HTablePool in favor of HConnection.getTable(...)

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.94.6, 0.95.0
• Fix Version/s: 0.98.0, 0.95.2, 0.94.11, 2.0.0
• Hadoop Flags: Reviewed

Release Note

This issue introduces a few new APIs:
* HConnectionManager:
{code}
    public static HConnection createConnection(Configuration conf)
    public static HConnection createConnection(Configuration conf, ExecutorService pool)
{code}
* HConnection:
{code}
    public HTableInterface getTable(String tableName) throws IOException
    public HTableInterface getTable(byte[] tableName) throws IOException
    public HTableInterface getTable(String tableName, ExecutorService pool) throws IOException
    public HTableInterface getTable(byte[] tableName, ExecutorService pool) throws IOException
{code}

By default HConnectionImplementation will create an ExecutorService when needed. The ExecutorService can optionally passed be passed in.
HTableInterfaces are retrieved from the HConnection. By default the HConnection's ExecutorService is used, but optionally that can be overridden for each HTable.

• Assignee: Lars Hofhansl
• Reporter: Lars Hofhansl
• Created: 14/Aug/12 05:04
• Updated: 06/Apr/18 04:34
• Resolved: 07/Aug/13 23:59

Description

Update:
I now propose deprecating HTablePool and instead introduce a getTable method on HConnection and allow HConnection to manage the ThreadPool.

Initial proposal:
Here I propose a very simple TablePool.
It could be called LightHTablePool (or something - if you have a better name).
Internally it would maintain an HConnection and an Executor service and each invocation of getTable(...) would create a new HTable and close() would just close it.
In testing I find this more light weight than HTablePool and easier to monitor in terms of resources used.

It would hardly be more than a few dozen lines of code.

Issue Links

• depends upon: HBASE-4805 Allow better control of resource consumption in HTable
• is related to: HBASE-6956 Do not return back to HTablePool closed connections
• relates to: HBASE-9117 Remove HTablePool and all HConnection pooling related APIs
• relates to: HBASE-7463 [REST] Use "unmanaged" HConnection instead of HTablePool