[PHOENIX-245] Support declaring primary key columns as REVERSE to avoid hotspotting

• Type: Task
• Status: Resolved
• Resolution: Fixed
• Labels: enhancement wontfix
• old issue number: 114
• Assignee: aaraujo
• Reporter: James R. Taylor
• Created: 10/Mar/14 23:46
• Updated: 16/Mar/14 07:18
• Resolved: 16/Mar/14 07:18

Description

One technique to prevent write hot-spotting when you have a monotonically increasing key is to reverse the bits. This works well if you don't need to do a range scan across the values. One use case is when your first column represents a tenant ID in a multi tenant system.

This would be implemented by building on the fix for [this issue](https://github.com/forcedotcom/phoenix/issues/58):

1. Add a new enum for REVERSE
2. Change the serialization/deserialization code in PDataType to reverse the bits in the case of REVERSE.
3. Disallow range scans on columns of type REVERSE. This could be caught in ExpressionCompiler_visitLeave(ComparisonParseNode,List<Expression>) and ExpressionCompiler_visitLeave(LikeParseNode,List<Expression>). These are the two cases I can think of that result in range scans.