[ATLAS-1369] Optimize Gremlin created by DSL Translator

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.8-incubating
• Assignee: Jeffrey Hagelberg
• Reporter: Jeffrey Hagelberg
• Created: 12/Dec/16 19:48
• Updated: 17/May/18 15:39
• Resolved: 03/Feb/17 14:40

Description

The way the queries are generated now, in many cases the indices are not used when executing queries. The main problem is that gremlin cannot currently use the graph indices to optimize the lookup for "has" expressions within an "and" or an "or". This JIRA introduces a GremlinQueryOptimizer that attempts to extract "has" expressions out of "and" expressions and turn "or" expressions into unions.

The code being submitted has only been tested with TP 3 at this point. There are some issues that need to be fixed before this can be used with TP 2:

• GremlinQueryOptimizer is currently disabled when using TP 2. The condition in AtlasRepositoryConfiguration.isGremlinOptimizerEnabled needs to be updated.
• FunctionGenerator - generates functions that take GraphTraversal as an argument. That should be changed to GreminPipeline when using TP 2. The return type should probably come from a new method in GremlinExpressionFactory
• loop support - for TP2, we will need to add logic to make sure that the loop call is not separated from the alias it references
• alias handling - the alias save/restore logic in ExpandOrsOptimization.getBaseResultExpression() may be need to adjusted for TP2
• possibly other issues, TBD

Issue Links

• links to: https://reviews.apache.org/r/54680/