I recently ran into an issue that I didn’t see coming. I was creating records, and then querying for them from the database.
I knew that they were created very close together in time, but they were created in two separate steps, so I knew that the timestamps would be different.
Only when I queried for them and compared the timestamps in my tests, I was getting the same timestamp back on both records.
After some digging I realized that the records had different timestamps in the database…where things were being measured in microseconds, but Javascript only tracks down to the millisecond, so under certain circumstances I was seeing one record round up and the other record round down such that the two of them were showing the exact same timestamp — to the millisecond on my in-memory object in Javascript.
I never would have expected to be in a situation where I needed or cared about more precision than 1/1000th of a second, but there you have it.