Experimental technique demonstrated by Stephen Margheim: abuse Active Record's three-tier multiple-database support to define a `reader` and `writer` configuration that both point to the same SQLite file. The reader pool opens read-only connections (letting SQLite optimize internally and reject writes), while the writer pool is limited to a single connection (moving linear-write serialization from SQLite's file lock up into Active Record where it's faster). A modified database-selector resolver defaults every web request to the reading role ('deferred requests'), and the Active Record `transaction` method is monkey-patched via `prepend` to switch to the writing role for just that operation. Eliminates connection-pool saturation where in-flight writes would starve concurrent reads. Opt-in and marked experimental in the enhanced-sqlite3-adapter gem.