I have been working on DAFFODIL-1444 which is about improving schema compilation space/speed.
I wanted to report on progress. Two schemas that take a long time to compile are EDIFACT and HL7-v2.7. I show below the improvement in schema compilation performance. I am comparing the current Daffodil 2.5.0 master as of 2019-12-05 15:00 US.ET (before), to my development sandbox (after). The test compiles the schema, and does a save of the compiled schema to a null output stream. before after EDIFACT 88 seconds 11 seconds HL7 35 seconds 5 seconds This is a factor of 7 to 8 or so on these schemas. Caveats: almost all optimizations are turned off, so runtime would be slow, and in fact without alignment optimizations many unparser tests fail due to circular deadlocks on forward-computed length. So next is putting the basic optimizations back in and getting all tests to work. There are additional improvements possible which should further improve schema compilation time substantially.
