Do not move datoms which create variables used in functions/not-join which are inside or-join

[nikolayandr]

Hi, sorry that I'm informing about issue instead to provide a solution, I just start to use this library in the java project which builds datalog queries from SQL dialect so Clojure is something very new for me :) Let me describe the cases when optimized queries became not executable by the datomic:

Original query:

[:find ?Root
:in ?typeName
:where
 [?Root :typeName ?typeName]
 (or-join [?Root] [(missing? ?Root :attribute)])
 ]

Optimized query is:

[:find ?Root
:in ?typeName
:where
 (or-join [(missing? ?Root :attribute)])
 [?Root :typeName ?typeName]
 ]

On attempt to execute such query Datomic says:
:db.error/insufficient-binding [?Root] not bound in expression clause: [(missing? $ ?Root :attribute)]

Similar situation is for a case when not-join is used within or-join
Original query:

[:find ?Root
:in ?typeName
:where
 [?Root :typeName ?typeName]
 (or-join
  [?Root]
  (not-join
    [?Root]
    [?Root :attribute _]
  )
 )
 ]

Optimized query is:

[:find ?Root
:in ?typeName
:where
 (or-join
  [?Root]
  (not-join
    [?Root]
    [?Root :attribute _]
  )
 )
 [?Root :typeName ?typeName]
 ]

[nikolayandr]

But makes sense to mention for the case not-join within or-join that if there is condition within or-join which populates ?Root then [?Root :typeName ?typeName] can be put at the bellow of total query, so the next optimized query will be executed

[:find ?Root
:in ?typeName
:where
 (or-join
  [?Root]
  (not-join
    [?Root]
    [?Root :attribute _]
  )
 [?Root :attr ?value]
 )
 [?Root :typeName ?typeName]
 ]

[nikolayandr]

UPD: Sorry, I did mistake about functions, main condition to reproduce issue: a function should be within or-join

[benkamphaus]

Thanks for the examples and good to see others are looking at using the library! Will reproduce and determine best resolution.