Module df_optimizer

Datafusion optimizer for flow plan

Structs

• AvgExpandRule 🔒
• CheckGroupByRule 🔒
  This rule check all group by exprs, and make sure they are also in select clause in a aggr query
• ExpandAvgRewriter 🔒
  rewrite avg(<expr>) function into CASE WHEN count(<expr>) !=0 THEN cast(sum((<expr>) AS avg_return_type)/count((<expr>) ELSE 0
• FindColumn 🔒
  Find all column names in a plan
• TumbleExpand
  This is a placeholder for tumble_start and tumble_end function, so that datafusion can recognize them as scalar function
• TumbleExpandRule 🔒
  expand tumble in aggr expr to tumble_start and tumble_end with column name like window_start

Functions

• apply_df_optimizer
• check_group_by_analyzer 🔒
  make sure everything in group by’s expr is in select
• expand_avg_analyzer 🔒
  expand avg(<expr>) function into cast(sum((<expr>) AS f64)/count((<expr>)
• expand_tumble_analyzer 🔒
  expand tumble in aggr expr to tumble_start and tumble_end, also expand related alias and column ref
• put_aggr_to_proj_analyzer 🔒
  lift aggr’s composite aggr_expr to outer proj, and leave aggr only with simple direct aggr expr i.e.
• sql_to_flow_plan
  To reuse existing code for parse sql, the sql is first parsed into a datafusion logical plan, then to a substrait plan, and finally to a flow plan.