Intern db info

[laurit]

Most applications should be using a connection pool that has a limited number of connections. The connections returned from that pool should be wrapped in a way that code in

opentelemetry-java-instrumentation/instrumentation/jdbc/library/src/main/java/io/opentelemetry/instrumentation/jdbc/internal/JdbcUtils.java

Line 24 in bfeb482

public static Connection connectionFromStatement(Statement statement) {

can unwrap them to the original connection that was returned from jdbc driver. If that is the case then we'll have a small number of DbInfo instances. If application does not use a connection pool or we are unable to unwrap connection to get the original one that already has DbInfo attached we'll end up with a large number of DbInfo instances which all contain the same data. I have a heap dump that has a bit under a million DbInfo instances consuming slightly less than 500mb.