2023-04-16

23c free - PL/SQL to SQL Transpiler - the CBOs area

As I'm checking for new and interesting parts in Oracles 23c free database, the PL/SQL to SQL Transpiler seems to be a very nice feature, and something I'd like to investigate. 

But before I started my work, a quick check at google showed Tim Hall had already created his post Automatic PL/SQL to SQL Transpiler in Oracle Database 23c. That's very good news as his articles have a very high quality and saved me a lot of time. 

When I followed his examples, I wondered which part of the Cost Based Optimizer does this work? 
So I started a little CBO trace (event 10053) . There I found these lines: 


FPD: Considering simple filter push in query block SEL$1 (#0)
"T1"."VAL1"+"T1"."VAL2"=300
try to generate transitive predicate from check constraints for query block SEL$1 (#0)
finally: "T1"."VAL1"+"T1"."VAL2"=300


and to map the acronym FPD to some meaningful content, at the top of the trace I found


FPD - filter push-down
  

There is nothing more of relevance in the trace file - or at least I didn't find anything. 
Also a quick check for hints, parameters or fix controls didn't create any matches. We only can enable the feature using set sql_transpiler = 'ON' on session or system level. 

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