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Im am keep getting ORA-06502: PL/SQL: numeric or value error: character string buffer too small. Here is what i do.

I have this piece of code (removed just the initialisation of variable that's rather long and outside the parallel region). I am testing it on a local machine (4 physical cores, 8 threads) and comparing speed and result with its serial version. When I run the code with more than 4 threads it seems to incur sometimes in some race condition and the final output (variable T written to disk after the parallel region) is different in the two cases. When I run with 4 or less threads everything is fine, both code run with the same number of iterations and give the final result. From the documentation, there is an implicit synchronisation at the end of each OMP DO block (unless you specify nowait).