Some last info: the problem disappears when using the no_mitosis_pipe optimizer pipeline.

sql>set optimizer='no_mitosis_pipe';

operation successful (0.139ms)

sql>SELECT * FROM source1 WHERE SUBSTRING(SOURCE,1,2)='04' LIMIT 1 OFFSET 400000;

+-----------------------------------------------------------------------------+--------+----------------------------------------------------------------------------------------------------------------------------------------------------+

| file                                                                        | line   | source                                                                                                                                             |

+=============================================================================+========+====================================================================================================================================================+

| /home/bkaptijn/DDDB/.tmpinputdir/9772_9999_20130501_20130531_Schade_516.ASC | 430664 | 04999999999999999999999999999999999999999

                                                                                                                                                :

+-----------------------------------------------------------------------------+--------+----------------------------------------------------------------------------------------------------------------------------------------------------+

1 tuple (1.1s)

sql>set optimizer='default_pipe';

operation successful (0.305ms)

sql>SELECT * FROM source1 WHERE SUBSTRING(SOURCE,1,2)='04' LIMIT 1 OFFSET 400000;

+------+------+--------+

| file | line | source |

+======+======+========+

+------+------+--------+

0 tuples (798.870ms)

Regards, Bas