Commits on Jan 22, 2020

1. Fix to #18555 - Query: when rewriting null semantics for comparisons … …

   …with functions use function specific metadata to get better SQL
   
   When we need to compute whether a function is null, we often can just evaluate nullability of it's constituents (instance & arguments), e.g.
   SUBSTRING(stringProperty, 0, 5) == null -> stringProperty == null
   
   Adding metadata to SqlFunctionExpression:
   nullResultAllowed - indicates whether function can ever be null,
   instancePropagatesNullability - indicates whether function instance can be used to calculate nullability of the entire function
   argumentsPropagateNullability - array indicating which (if any) function arguments can be used to calculate nullability of the entire function
   
   If "canBeNull" is set to false we can instantly compute IsNull/IsNotNull of that function.
   Otherwise, we look at values of instancePropagatesNullability and argumentsPropagateNullability - if any of them are set to true, we use corresponding argument(s) to compute function nullability.
   If all of them are set to false we must fallback to the old method and evaluate nullability of the entire function.
   
   Resolves #18555

   

   maumar committed Jan 22, 2020
   Configuration menu

   • View commit details
   • Copy full SHA for d75a0e5
   • Browse repository at this point

   Copy the full SHA

   d75a0e5 View commit details

   Browse the repository at this point in the history