There are some issues that come up with database tables that are 
expected to be used in shared scans. It would be good to have fields in 
CSS that indicate if a table should be locked in memory for a shared 
scan and its priority/speed of scan. We only want to have a few high use 
tables getting locked in memory when they are needed so that they are 
only loaded once and used by multiple queries. The only tables currently 
expected to get locked in memory are Object, Source, Object_extra, and 
Forced but this will probably change and I'd like to build the code so 
that it does this automatically off of information in CSS.

The priority/speed of a table is an indication of how long a query using 
that table will take and how the table is used.
- Object, while being a fairly large table is considered fast/high 
priority. It can often be used in a query by itself.
- Source and ForcedSource are fairly large and usually are joined with 
Object, so they are medium speed/priority
- Object_extra is expected to be quite large and need to join with 
Object, so it is slow low priority.

The point being the speed/priority of a table should be in CSS so that 
the czar can decide during analysis if a query should be fast (finish in 
about an hour), medium (about 6 hours), or slow (12 hours). This also 
means that code will need to be added to the czar to do this and pass 
the information to the worker.

Any thoughts on the best way to do this? Other concerns?

########################################################################
Use REPLY-ALL to reply to list

To unsubscribe from the QSERV-L list, click the following link:
https://listserv.slac.stanford.edu/cgi-bin/wa?SUBED1=QSERV-L&A=1