rowCount not always equal to rows.length

[Developerarif2]

Since upgrading to pg 4.x javascript from pg 2.11.1 native, we have seen a variety of nasty failures in production under load. one of my engineers had a theory, and it proved correct: we saw in production over the weekend a case where the results returned from pg were internally inconsistent: results.rowCount was 1, but results.rows.length was 0. Our codebase has been using these two properties interchangeably, which led to some very nasty bugs. We do not currently have a repro case for this, but seems to happen on an error path under load. This was using pg 4.5.1 javascript, plus PR brianc/node-postgres#961.

I would caution everyone to avoid using the rowCount property until we get to the bottom of this.

For now we have now rolled back to pg 2.11.1 native in production.