This PR shouldresolvecoder/internal#719 by limiting theworkspace_builds rows selected by the query to the most recent 100 builds of a template, as opposed to all builds in the last 30d. For our own internal templates with the most builds (1700-2000 in a 30d period) this should cut the query execution time by about 80%.

Unless we have some restriction on keeping the 30d period, contract related or otherwise, this seems like a safe change to make. In addition to the execution speed improvements it also means the memory for the query is bounded as well.

If we want to keep a 30d time period for the avg build time value I think it's worth exploring a purpose built solution such as histogram structures where the build times could be bucketized by template ID as they're observed.