Testing Presto JDBC Timezone Support

presto_jdbc_timezones.clj

(defn- unwrap-connection ^PrestoConnection [^C3P0ProxyConnection conn]
  (.unwrap conn PrestoConnection))

(defn set-timezone! [conn ^String zone-id]
  (.setTimeZoneId (unwrap-connection conn) zone-id))

(defn get-timestamp-utc [^com.facebook.presto.jdbc.PrestoResultSet rset ^Integer index]
  (let [method (doto (.getDeclaredMethod com.facebook.presto.jdbc.PrestoResultSet
                                         "getTimestamp"
                                         (into-array Class [Integer/TYPE com.facebook.presto.jdbc.internal.joda.time.DateTimeZone]))
                 (.setAccessible true))
        zone (com.facebook.presto.jdbc.internal.joda.time.DateTimeZone/UTC)]
    (.invoke method rset (object-array [(int index) zone]))))

(defn x []
  (into {} (for [timezone ["UTC" "US/Pacific"]]
             [timezone
              (with-open [conn (doto (java.sql.DriverManager/getConnection "jdbc:presto://localhost:8080/test_data/default?user=metabase")
                                 (set-timezone! timezone))
                          stmt (.prepareStatement conn (str "SELECT"
                                                            " TIMESTAMP '2021-06-15 06:54:00.000 America/Los_Angeles' AS tz,"
                                                            " TIMESTAMP '2021-06-15 06:54:00.000' AS no_tz"))
                          rset (.executeQuery stmt)]
                (let [session-timezone (.getTimeZoneId (unwrap-connection conn))]
                  (assert (= session-timezone timezone))
                  (when (.next rset)
                    {:tz    {:default                (.getObject rset 1)
                             :java-sql-timestamp     (.getTimestamp rset 1)
                             :java-sql-timestamp-utc (get-timestamp-utc rset 1)
                             :string                 (.getString rset 1)
                             :parsed                 (some-> (.getString rset 1) u.date/parse)}
                     :no-tz {:default                (.getObject rset 2)
                             :java-sql-timestamp     (.getTimestamp rset 2)
                             :java-sql-timestamp-utc (get-timestamp-utc rset 2)
                             :string                 (.getString rset 2)
                             :parsed                 (some-> (.getString rset 2) u.date/parse)
                             :parsed-in-session-zone (some-> (.getString rset 2)
                                                             u.date/parse
                                                             (u.date/with-time-zone-same-instant session-timezone))}})))])))