[HBASE-25278] Add option to toggle CACHE_BLOCKS in count.rb

• Type: New Feature
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.4.0
• Component/s: shell
• Hadoop Flags: Reviewed

Release Note

A new option, CACHE_BLOCKS, was added to the `count` shell command which will force the data for a table to be loaded into the block cache. By default, the `count` command will not cache any blocks. This option can serve as a means to for a table's data to be loaded into block cache on demand. See the help message on the count shell command for usage details.

• Assignee: Josh Elser
• Reporter: Josh Elser
• Created: 12/Nov/20 21:03
• Updated: 16/Apr/21 12:08
• Resolved: 24/Nov/20 15:14

Description

A trick I've found myself doing a couple of times (hat-tip to psomogyi) is to edit table.rb so that the `count` shell command will not instruct RegionServers to not cache any data blocks. This is a quick+dirty way to force a table to be loaded into block cache (i.e. for performance testing).

We can easily add another option to avoid having to edit the ruby files.

Issue Links

• is a parent of: HBASE-25781 Add cacheBlocks option to RowCounter
• links to: GitHub Pull Request #2650