Merge pull request #158 from mbezjak/migrations-table-exists-sql

Add :migrations-table-exists-sql option
weavejester · Nov 6, 2024 · 624da4c · 624da4c
2 parents 9aab515 + 120b75b
commit 624da4c
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Showing 4 changed files with 87 additions and 18 deletions.
diff --git a/jdbc/src/ragtime/jdbc.clj b/jdbc/src/ragtime/jdbc.clj
@@ -35,32 +35,44 @@
                        (str (:table_schem metadata) "." (:table_name metadata))
                        (:table_name metadata))))
 
-(defn- table-exists? [db-spec ^String table-name]
+(defn- table-exists-via-metadata-scan? [db-spec ^String table-name]
   (some (partial metadata-matches-table? table-name)
         (get-table-metadata db-spec)))
 
-(defn- ensure-migrations-table-exists [db-spec migrations-table]
-  (when-not (table-exists? db-spec migrations-table)
+(defn- table-exists-via-provided-sql? [db-spec sql]
+  (pos? (count (sql/query db-spec [sql]))))
+
+(defn- table-exists? [datasource table-name migrations-table-exists-sql]
+  (if migrations-table-exists-sql
+    (table-exists-via-provided-sql? datasource migrations-table-exists-sql)
+    (table-exists-via-metadata-scan? datasource table-name)))
+
+(defn- ensure-migrations-table-exists
+  [db-spec migrations-table migrations-table-exists-sql]
+  (when-not (table-exists? db-spec migrations-table migrations-table-exists-sql)
     (sql/execute! db-spec [(migrations-table-ddl migrations-table)])))
 
 (defn- format-datetime [^Date dt]
   (-> (SimpleDateFormat. "yyyy-MM-dd'T'HH:mm:ss.SSS")
       (.format dt)))
 
-(defrecord SqlDatabase [db-spec migrations-table]
+(defrecord SqlDatabase [db-spec migrations-table migrations-table-exists-sql]
   p/DataStore
   (add-migration-id [_ id]
-    (ensure-migrations-table-exists db-spec migrations-table)
+    (ensure-migrations-table-exists db-spec migrations-table
+                                    migrations-table-exists-sql)
     (sql/insert! db-spec migrations-table
                  {:id         (str id)
                   :created_at (format-datetime (Date.))}))
 
   (remove-migration-id [_ id]
-    (ensure-migrations-table-exists db-spec migrations-table)
+    (ensure-migrations-table-exists db-spec migrations-table
+                                    migrations-table-exists-sql)
     (sql/delete! db-spec migrations-table ["id = ?" id]))
 
   (applied-migration-ids [_]
-    (ensure-migrations-table-exists db-spec migrations-table)
+    (ensure-migrations-table-exists db-spec migrations-table
+                                    migrations-table-exists-sql)
     (sql/query db-spec
                [(str "SELECT id FROM " migrations-table " ORDER BY created_at")]
                {:row-fn :id})))
@@ -70,11 +82,17 @@
   The following options are allowed:
 
   :migrations-table - the name of the table to store the applied migrations
-                      (defaults to ragtime_migrations)"
+                      (defaults to ragtime_migrations)
+
+  :migrations-table-exists-sql - SQL string to check if migrations table
+                                 exists. If not supplied, database metadata is
+                                 used instead, which can be slow for large DBs."
   ([db-spec]
    (sql-database db-spec {}))
   ([db-spec options]
-   (->SqlDatabase db-spec (:migrations-table options "ragtime_migrations"))))
+   (->SqlDatabase db-spec
+                  (:migrations-table options "ragtime_migrations")
+                  (:migrations-table-exists-sql options))))
 
 (defn- execute-sql! [db-spec statements transaction?]
   (doseq [s statements]

diff --git a/jdbc/test/ragtime/jdbc_test.clj b/jdbc/test/ragtime/jdbc_test.clj
@@ -36,6 +36,20 @@
     (is (= ["20" "21"]
            (sql/query (:db-spec db) ["SELECT * FROM myschema.migrations"] {:row-fn :id})))))
 
+(deftest test-migrations-table-exists-sql
+  (let [migrations-table-exists-sql (str "SELECT * FROM INFORMATION_SCHEMA.TABLES"
+                                         " WHERE TABLE_CATALOG='TESTDB'"
+                                         " AND TABLE_NAME='RAGTIME_MIGRATIONS'")
+        db (jdbc/sql-database db-spec
+                              {:migrations-table-exists-sql migrations-table-exists-sql})]
+    (p/add-migration-id db "12")
+    (is (= ["12"]
+           (sql/query (:db-spec db) ["SELECT * FROM ragtime_migrations"] {:row-fn :id})))
+
+    (p/add-migration-id db "13")
+    (is (= ["12" "13"]
+           (sql/query (:db-spec db) ["SELECT * FROM ragtime_migrations"] {:row-fn :id})))))
+
 (defn table-names [db]
   (set (sql/query (:db-spec db) ["SHOW TABLES"] {:row-fn :table_name})))
 

diff --git a/next-jdbc/src/ragtime/next_jdbc.clj b/next-jdbc/src/ragtime/next_jdbc.clj
@@ -60,14 +60,24 @@
                        (str table_schem "." table_name)
                        table_name)))
 
-(defn- table-exists? [datasource ^String table-name]
+(defn- table-exists-via-metadata-scan? [datasource ^String table-name]
   (let [{:keys [tables quote]} (get-db-metadata datasource)
         table-name-unquoted    (unquote-table-name quote table-name)]
     (some (partial metadata-matches-table? table-name-unquoted)
           tables)))
 
-(defn- ensure-migrations-table-exists [datasource migrations-table]
-  (when-not (table-exists? datasource migrations-table)
+(defn- table-exists-via-provided-sql? [datasource sql]
+  (pos? (count (jdbc/execute! datasource [sql]))))
+
+(defn- table-exists? [datasource table-name migrations-table-exists-sql]
+  (if migrations-table-exists-sql
+    (table-exists-via-provided-sql? datasource migrations-table-exists-sql)
+    (table-exists-via-metadata-scan? datasource table-name)))
+
+(defn- ensure-migrations-table-exists
+  [datasource migrations-table migrations-table-exists-sql]
+  (when-not (table-exists? datasource migrations-table
+                           migrations-table-exists-sql)
     (let [sql (str "create table " migrations-table
                    " (id varchar(255) primary key, created_at varchar(32))")]
       (jdbc/execute! datasource [sql]))))
@@ -76,20 +86,23 @@
   (-> (SimpleDateFormat. "yyyy-MM-dd'T'HH:mm:ss.SSS")
       (.format dt)))
 
-(defrecord SqlDatabase [datasource migrations-table]
+(defrecord SqlDatabase [datasource migrations-table migrations-table-exists-sql]
   p/DataStore
   (add-migration-id [_ id]
-    (ensure-migrations-table-exists datasource migrations-table)
+    (ensure-migrations-table-exists datasource migrations-table
+                                    migrations-table-exists-sql)
     (sql/insert! datasource migrations-table
                  {:id         (str id)
                   :created_at (format-datetime (Date.))}))
 
   (remove-migration-id [_ id]
-    (ensure-migrations-table-exists datasource migrations-table)
+    (ensure-migrations-table-exists datasource migrations-table
+                                    migrations-table-exists-sql)
     (sql/delete! datasource migrations-table ["id = ?" id]))
 
   (applied-migration-ids [_]
-    (ensure-migrations-table-exists datasource migrations-table)
+    (ensure-migrations-table-exists datasource migrations-table
+                                    migrations-table-exists-sql)
     (let [sql [(str "SELECT id FROM " migrations-table " ORDER BY created_at")]]
       (->> (sql/query datasource sql {:builder-fn rs/as-unqualified-lower-maps})
            (map :id)))))
@@ -101,11 +114,17 @@
   :migrations-table - the name of the table to store the applied migrations
                       (defaults to ragtime_migrations). You must include the
                       schema name if your DB supports that and you are not
-                      using the default one (ex.: myschema.migrations)"
+                      using the default one (ex.: myschema.migrations)
+
+  :migrations-table-exists-sql - SQL string to check if migrations table
+                                 exists. If not supplied, database metadata is
+                                 used instead, which can be slow for large DBs."
   ([datasource]
    (sql-database datasource {}))
   ([datasource options]
-   (->SqlDatabase datasource (:migrations-table options "ragtime_migrations"))))
+   (->SqlDatabase datasource
+                  (:migrations-table options "ragtime_migrations")
+                  (:migrations-table-exists-sql options))))
 
 (defn- execute-sql! [datasource statements transaction?]
   (if transaction?

diff --git a/next-jdbc/test/ragtime/next_jdbc_test.clj b/next-jdbc/test/ragtime/next_jdbc_test.clj
@@ -53,6 +53,24 @@
                 (n.j/execute! (:datasource db))
                 (map :MIGRATIONS/ID))))))
 
+(deftest test-migrations-table-exists-sql
+  (let [migrations-table-exists-sql (str "SELECT * FROM INFORMATION_SCHEMA.TABLES"
+                                         " WHERE TABLE_CATALOG='TESTDB'"
+                                         " AND TABLE_NAME='RAGTIME_MIGRATIONS'")
+        db (jdbc/sql-database datasource
+                              {:migrations-table-exists-sql migrations-table-exists-sql})]
+    (p/add-migration-id db "12")
+    (is (= ["12"]
+           (->> ["SELECT * FROM ragtime_migrations"]
+                (sql/query (:datasource db))
+                (map :RAGTIME_MIGRATIONS/ID))))
+
+    (p/add-migration-id db "13")
+    (is (= ["12" "13"]
+           (->> ["SELECT * FROM ragtime_migrations"]
+                (sql/query (:datasource db))
+                (map :RAGTIME_MIGRATIONS/ID))))))
+
 (defn table-names [db]
   (set (map :TABLES/TABLE_NAME (sql/query (:datasource db) ["SHOW TABLES"]))))