Queries typically take a few minutes to execute. The
options "email URL of compressed text file" or "email URL of
compressed FITS archive" run in the background.
The mSQL database is shutdown everyday around 06:30 local
time while the scratch area is cleared. Queries running at
this time will die, and results from earlier queries will be
deleted.
Having data returned as an HTML table is really only
suitable for queries returning relatively small numbers of
database entries, especially where you wish to view the
images and spectra. Large queries are best returned as a
compressed text files. If you wish to view large numbers of
images or spectra you should break your queries down into
limited ranges of serial numbers.
Using the ORDER BY construction to sort the returned
entries is not recommended for large queries, for which it is
better to sort the returned text file off-line.
The various parameters kept as real numbers in the database
are held with differing precisions. For example, the fields
with upper-case names were written using Fortran free-format,
which causes the precision to vary with the value of the
number; the fields with lower-case names were written using a
fixed format.