Query stops before processing entire file!

When running a job/update process that uses a query, we got an Appx error during the selecting records phase. This was about 10000 records into the file, out of ~180000, and stated that it couldn't scratch the work file because the record length was invalid.

That's caused by a known bug in earlier versions of Appx. You can work around that problem by setting an environment variable, try this:

APPX_RUN_MEM=2097150

This tells Appx to allocate 2MB to process a give query before it falls back to using an on-disk sort strategy.