How can I make my very large catalog query run faster?
Posted by Vandana Desai on 26 November 2013 12:08 PM

Here are some tips for making your large catalog search return faster:

1. If you suspect that your query might return results larger than 2 Gb, you will need to break it up into smaller queries. It can be difficult to predict the size of the returned results. It depends on the constraints you are interested in, the number of columns you want, and the density of objects on the sky. You can do a test on a 1 sq deg patch of the sky, for instance, and scale up until the result is just under 2 Gb.

2. Query on indexed columns as much as possible. If you are using the web interface, you can see which columns are indexed in the table that allows you to select which columns to download. The indexed columns are marked with an X. For the AllWISE catalog, the indexed columns are dec and glat.

3. Polygon searches do take advantage of the spatial indexing. If users have spatial constraints, they can be entered as polygon limits or entered into the column constraint table.

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