Approaches

Problem statement

Execution time increases with compilation. But, compilation gives better performance. On the other hand, pre-compiled headers provide quickstart for execution but have runtime disadvantages.

Approach

Combining compilation and pre-compiled execution. Pre-compiled execution provides quickstart for execution with compilation running on the background --> hiding compilation with pre-compiled headers

Possible options

1. compile complete query while partial results are generated by pre-compiled headers
2. partial compilation of a query while pre-compiled headers finish the remaining operators

compiling the complete query

user is given partial results with slower execution until compiled, afterward, faster results are produced advantages

• partial results are generated; i.e. fast response time
• no need for data transfer from one paradigm to another
• both the models can work in parallel

disadvantage

• generation of complete query requires more compilation time
• Data sharing is problematic across these paradigms
• Resources are wasted on both the paradigms as they share the execution
• Optimal execution from both the paradigms are not combined, i.e. advantage of one paradigm could be counteracted by another

Compiling partial query

results from pre-compiled headers are streamed into compiled execution once partial compilation ends. Pipeline-breakers can be used to connect from one paradigm to another.

advantages

• Complete resource utilization by compilation
• partial compilation leads to reduced compilation time than compiling a complete query

disadvantages

• Requires the right point to connect these paradigms; else leads to under-utilization of resources
• Transfer of result from one paradigm to another is problematic as the formats have to be changed
• Queries without pipeline-breakers cannot stream results
• pre-compiled headers process in a column-oriented and compiled executes in tuple-at-a-time, this conversion is again problematic
• requires the complete data to be produced by pre-compiled headers to feed into compiled execution