add more info on init_callbacks to README.md

funbringer · web-flow · commit c61cb6228436 · 2016-10-06T17:11:34.000+04:00
diff --git a/README.md b/README.md
@@ -209,7 +209,24 @@ Enable/disable auto partition propagation (only for RANGE partitioning). It is e
 ```plpgsql
 set_init_callback(relation REGCLASS, callback REGPROC DEFAULT 0)
 ```
-Set partition creation callback to be invoked for each attached or created partition (both HASH and RANGE).
+Set partition creation callback to be invoked for each attached or created partition (both HASH and RANGE). The callback must have the following signature: `part_init_callback(args JSONB) RETURNS VOID`. Parameter `arg` consists of several fields whose presence depends on partitioning type:
+```json
+/* RANGE-partitioned table abc (child abc_4) */
+{
+    "parent":    "abc",
+    "parttype":  "2",
+    "partition": "abc_4",
+    "range_max": "401",
+    "range_min": "301"
+}
+
+/* HASH-partitioned table abc (child abc_0) */
+{
+    "parent":    "abc",
+    "parttype":  "1",
+    "partition": "abc_0"
+}
+```
 
 ## Views and tables
 
