ContinuumIO/blaze — pull request #276 by mrocklin (2014-05-20 19:34:39+00:00)
Title: Performance tweaks

I played around with optimizing a couple of standard operations in streaming Python. Here are the results:

1. We no longer use blaze.utils.get inside inner loops in csv. This cuts down the cost of queries like `dd[:, [field1, field2]]` by about an order of magnitude.
2. After this type coercion through DyND dominates runtimes.
3. `SQL.extend` is faster about coercing tuples into dicts. In a data migration the sqlite backend now dominates runtimes.
4. I've also increased the size of the DyND block in `blaze.data.utils.coerce` to 1000. This gave a 10% boost to a runtime, could also have been just noise.