simplify

Author: jaydeluca

instrumentation/jdbc/README.md

@@ -9,23 +9,9 @@
 
 ## Connection Pool Unwrapping
 
-The JDBC instrumentation requires unwrapping pooled connections (via `java.sql.Wrapper`) to
-correctly attribute database operations to the underlying connection and to cache metadata. Most
-connection pools support this by default.
+The instrumentation unwraps pooled connections (via java.sql.Wrapper) to cache database metadata
+against the underlying physical connection. Most connection pools support this by default.
 
-**Performance issue?** If unwrapping fails, the instrumentation may have degraded performance or
-increased overhead with some JDBC drivers. Metadata extraction may result in database queries on
-every operation (depending on driver implementation and caching behavior) instead of being cached,
-and operations may be attributed to the wrong database connection. To fix, ensure your connection
-pool supports unwrapping:
-
-**Vibur DBCP example:**
-```java
-ds.setAllowUnwrapping(true);
-```
-
-**Custom wrappers:** Implement `java.sql.Wrapper` correctly to delegate `isWrapperFor()` and
-`unwrap()` to the underlying connection.
-
-**Failover note:** Cached metadata uses the unwrapped connection object as the key. If your pool
-reuses the same connection object after failover, telemetry may show stale host attributes.
+In the case that a connection pool doesn't support this, caching is limited
+to the wrapper instance, which typically changes each time a connection is retrieved from the pool.
+This can result in repeated metadata extraction, potentially causing performance degradation.