storage: reuse transaction for uploads

Reuse a single transaction for all INSERT statements for a single
upload. This cuts about 50% of the runtime off an invocation of
the tests with -cloud, and about 25% of the runtime off an /upload run
on App Engine.

Change-Id: I90068f60420cfb67ae693f18ed83b341c2e483bd
Reviewed-on: https://go-review.googlesource.com/35069
Reviewed-by: Russ Cox <rsc@golang.org>
3 files changed
tree: 43a0b441e444c08f7a188f7509b6d469dd5bce57
  1. cmd/
  2. storage/
  3. AUTHORS
  4. CONTRIBUTING.md
  5. CONTRIBUTORS
  6. LICENSE
  7. PATENTS
  8. README