Flattening the table hierarchy

Recall that the SETI@home database uses a hierarchy of tables. In processing signals there are several places where we need information from higher-level tables. Nebula "flattens" the table hierarchy to create arrays, indexed by result ID, of these items. Given a signal (which contains a result ID) we can immediately look up the info in these arrays, without accessing other tables.

Flattening the table hierarchy

The needed files are created by "pushing down" information, starting from the tape table and working down. Memory-mapped files are used at each step. The steps are as follows: The resulting files are 12.1 GB (angle range, 32-bit float), 3.1 GB (beam number, 8-bit integer) and 375 MB (redundant flag, 1 bit).
Next: The Nebula pipeline.



 
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SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.