While warming the pages, I see 0 in the Time column of the Warmer Log. Does it mean that the pages are not warmed?

While warming the pages, I see 0 in the Time column of the Warmer Log. Does it mean that the pages are not warmed?

After warming the pages, the Time column in the Warmer Log sometimes contains 0 value. However, it does not mean that the pages are not warmed. By default, the extension takes the CURRENT_TIMESTAMP value from the database, transforms it and rounds it down. 

But if the page was warmed asynchronously, meaning that Enable Multi-Process Warming setting is activated, then the 0 value is expected in the Time column. The extension cannot detect the time it takes to warm the page, so 0 is recorded instead.