I'm working on a project which needs query the sql server many times to pull the statistics info. the whole process is very slow. so, I'm trying to use the multithread to do the work. However, I noticed one weird thing:
In the program, I need pull, say 10000 documents from the sql to local PC, then can do some analysis. Each document size is different. If I used 1 thread, say for document A whose size is 5MB, it will take about 20 seconds for the SELECT query returns the
result. Now, if I used 10 threads, I found that it will take much longer time for SQL to return the SELECT query for document A, say maybe 90 seconds. I got the run time for the SELECT from the sql profiler.
Overall, the performance of multithread is very similar to single thread even I use 50 threads. I used the same code for another project, the only difference is that that project scrapes data from website and this project gets data from sql. The other project
works very well when using multithread. so, I'm kind of believe that the multithread part code works fine.
Could this because some settings on sql server? some bandwidth limitation? any clues?
any help/suggestion will be appreciated.
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