fix issue with postgres driver treatment of clob values, which was causing us...

fix issue with postgres driver treatment of clob values, which was causing us to lose some data in the migration.

src/metabase/cmd/load_from_h2.clj

@@ -5,6 +5,7 @@
             [colorize.core :as color]
             (korma [core :as k]
                    [db :as kdb])
+            [medley.core :as m]
             [metabase.config :as config]
             [metabase.db :as db]
             (metabase.models [activity :refer [Activity]]
@@ -78,6 +79,10 @@
   "Entities that do NOT use an auto incrementing ID column."
   #{Setting Session})
 
+(def ^:private ^:dynamic *db-conn*
+  "Active database connection to the target database we are loading into."
+  nil)
+
 (defn- insert-entity [e objs]
   (print (u/format-color 'blue "Transfering %d instances of %s..." (count objs) (:name e)))
   (flush)
@@ -106,12 +111,11 @@
 (defn- set-postgres-sequence-values []
   (print (u/format-color 'blue "Setting postgres sequence ids to proper values..."))
   (flush)
-  (jdbc/with-db-transaction [conn (db/jdbc-details @db/db-connection-details)]
-    (doseq [e    (filter #(not (contains? entities-without-autoinc-ids %)) entities)
-            :let [table-name (:table e)
-                  seq-name   (str table-name "_id_seq")
-                  sql        (format "SELECT setval('%s', COALESCE((SELECT MAX(id) FROM %s), 1), true) as val" seq-name table-name)]]
-      (jdbc/db-query-with-resultset conn [sql] :val)))
+  (doseq [e    (filter #(not (contains? entities-without-autoinc-ids %)) entities)
+          :let [table-name (:table e)
+                seq-name   (str table-name "_id_seq")
+                sql        (format "SELECT setval('%s', COALESCE((SELECT MAX(id) FROM %s), 1), true) as val" seq-name table-name)]]
+    (jdbc/db-query-with-resultset *db-conn* [sql] :val))
   (println (color/green "[OK]")))
 
 (defn load-from-h2
@@ -122,11 +126,15 @@
   [h2-connection-string-or-nil]
   (db/setup-db)
   (let [h2-filename (or h2-connection-string-or-nil @metabase.db/db-file)]
-    ;; TODO - would be nice to add `ACCESS_MODE_DATA=r` but it doesn't work with `AUTO_SERVER=TRUE`
-    (jdbc/with-db-connection [h2-spec (db/jdbc-details {:type :h2, :db (str h2-filename ";IFEXISTS=TRUE")})]
+    ;; NOTE: would be nice to add `ACCESS_MODE_DATA=r` but it doesn't work with `AUTO_SERVER=TRUE`
+    ;; connect to H2 database, which is what we are migrating from
+    (jdbc/with-db-connection [h2-conn (db/jdbc-details {:type :h2, :db (str h2-filename ";IFEXISTS=TRUE")})]
       (kdb/transaction
         (doseq [e     entities
-                :let  [objs (jdbc/query h2-spec [(str "SELECT * FROM " (:table e))])]
+                :let  [objs (->> (jdbc/query h2-conn [(str "SELECT * FROM " (:table e))])
+                                 ;; we apply jdbc-clob->str to all row values because H2->Postgres
+                                 ;; gets messed up if the value is left as a clob
+                                 (map #(m/map-vals u/jdbc-clob->str %)))]
                 :when (seq objs)]
           (if-not (contains? self-referencing-entities e)
             (insert-entity e objs)
@@ -134,4 +142,6 @@
 
     ;; if we are loading into a postgres db then we need to update sequence nextvals
     (when (= (config/config-str :mb-db-type) "postgres")
-      (set-postgres-sequence-values))))
+      (jdbc/with-db-transaction [targetdb-conn (db/jdbc-details @db/db-connection-details)]
+        (binding [*db-conn* targetdb-conn]
+          (set-postgres-sequence-values))))))