On Monday, August 27, 2012 8:50:15 AM UTC-7, Ulrich Eckhardt wrote: > Am 27.08.2012 03:23, schrieb bruceg113...@gmail.com: > > > My program uses Python 2.6 and Sqlite3 and connects to a network > > > database 100 miles away. > > > > Wait, isn't SQLite completely file-based? In that case, SQLite accesses > > a file, which in turn is stored on a remote filesystem. This means that > > there are other components involved here, namely your OS, the network > > (bandwidth & latency), the network filesystem and the filesystem on the > > remote machine. It would help if you told us what you have there. > > > > > > > My program reads approx 60 records (4000 bytes) from a Sqlite > > > database in less than a second. Each time the user requests data, my > > > program can continuously read 60 records in less than a second. > > > However, if I access the network drive (e.g. DOS command DIR /S) > > > while my program is running, my program takes 20 seconds to read the > > > same 60 records. If I restart my program, my program once again takes > > > less than a second to read 60 records. > > > > Questions here: > > 1. Is each record 4kB or are all 60 records together 4kB? > > 2. Does the time for reading double when you double the number of > > records? Typically you have B + C * N, but it would be interesting to > > know the bias B and the actual time (and size) of each record. > > 3. How does the timing change when running dir/s? > > 4. What if you run two instances of your program? > > 5. Is the duration is only reset by restarting the program or does it > > also decrease when the dir/s call has finished? What if you close and > > reopen the database without terminating the program? > > > > My guess is that the concurrent access by another program causes the > > accesses to become synchronized, while before most of the data is > > cached. That would cause a complete roundtrip between the two machines > > for every access, which can easily blow up the timing via the latency. > > > > In any case, I would try Python 2.7 in case this is a bug that was > > already fixed. > > > > Good luck! > > > > Uli
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