pabloa98> the table baseline_denull has 1765 columns,
Uhh...
#define MaxHeapAttributeNumber 1600 /* 8 * 200 */
Did you modify that?
(The back of my envelope says that on 64bit, the largest usable t_hoff would be 248, of which 23 is fixed overhead leaving 225 as the max null bitmap size, giving a hard limit of 1800 for MaxTupleAttributeNumber and 1799 for MaxHeapAttributeNumber. And the concerns expressed in the comments above those #defines would obviously apply.)
