Full Answer

Since June 2026, Google's BigQuery Data Transfer Service caps backfills at 37 months from the current date. This reversed an 18-month-old policy that promised an 11-year window. A manual backfill that crosses the boundary does not simply fail — it overwrites existing historical rows with empty values, destroying data the store already owned. WooCommerce stores relying on the DTS connector as their long-term archive risk silent data destruction unless they snapshot existing tables and route future events through a pipeline they control. That is the short version. Here is what it means in practice for WooCommerce store owners who rely on this data for budget decisions.

The mechanism behind this change matters because it affects how ad platforms receive the signals they use for optimisation. When the data pathway breaks or changes format, the algorithms that allocate your budget lose the feedback loop they depend on. The result is not just missing reports — it is campaigns optimising against incomplete information, which compounds into wasted spend over weeks and months.

The practical fix is straightforward but not automatic. Store owners need to verify their current integration still delivers data in the format the receiving platform expects. A server-side event pipeline handles this by routing conversion data directly from WooCommerce to each destination in the correct format, independent of browser-side changes. For a deeper look at how this connects to your broader tracking architecture, see Google Just Walled Off Your Historical Data — BigQuery Data Transfer B.

The stores that act on this quickly preserve their optimisation history. The ones that wait discover the gap weeks later, when campaign performance has already degraded and the missing data cannot be backfilled.