|Introduction to SQL|
|Form Query User Guide|
|SkyServer Traffic Page|
|Contact Help Desk|
Due to the sheer size of the SDSS databases, queries that search the entire TB database (BEST or TARG), or queries that are not formulated in the most efficient way, can take a very long time to execute (hours). To be fair to other users and prevent the CAS from bogging down, the SkyServer search tools have built-in timeouts and row limits (max. number of rows in query results). These are listed below for eachtool.
If your query is timing out, please see the Optimizing Queries section of the SQL Intro Page.
If you absolutely need to run a query that does not fit within these limits, you can use the Batch Query system (CasJobs), which lets you run longer queries in separate queues and lets you maintain your own storage space on the DB server (MyDB).
If none of these options work, we may be able to make special arrangements for you to obtain the data that you need. Please contact the helpdesk in that case.