Use prefix trees instead of hashmaps to keep the engine state
commit all series in one request
fix a brittle test
Don't do the cross product if we don't have to
don't write too much data at once
some memory optimizations
reduce the default response buffer size
make writes synchronous for continuous queries
fixup! make writes synchronous for continuous queries
remove some debugging statements
Merge pull request #473 from influxdb/fix-patricks-crash

Reduce the memory utilization of the engine when the cardinality of the group by columns is big