[Mondrian] SqlTupleReader.readTuples generates huge IN list causing java.sql.SQLException

[Julian Hyde]

> Robin Tharappel wrote:
>
> We tried setting the maxConstraints = 100 however the same 
> error occurred. It looks like this issue is caused in part by 
> the large volume dimension at the parent level (200,000). 
> 
> There appears to be some code that results in the in clause 
> not to be created (from Mondrian 2.2.2 source for class 
> SqlConstraintUtil):
> 
>             ColumnConstraint[] cc = getColumnConstraints(c);
> 
>             if (!strict && cc.length >=
> MondrianProperties.instance().MaxConstraints.get()){
>                 // Simply get them all, do not create where-clause.
>                 // Below are two alternative approaches (and 
> code). They
>                 // both have problems.
> 
>             } else {
>                 String cond = 
> RolapStar.Column.createInExpr(q, cc, level.isNumeric());
>                 sqlQuery.addWhere(cond);
>             }
>             if (level.isUnique()) {
>                 break; // no further qualification needed
>             }
> In our case the number of ColumnConstraints (200,000) exceeds 
> the max constraint property (100), however the strict 
> variable is always true.
> Under what circumstances would this be false? We also tried Mondrian
> 2.3.2 but received the same error. 

I would approach this by running the code in the debugger. The simplest
explanation is that the code below is not hit - because this code is part of
the semi-join generation to implement non-empty.

I would do this if I had time and a reproducible testcase but right now I
don't have either. :) 

Julian