add more comments, remove completed tasks from README.md

Author: funbringer

README.md

@@ -38,7 +38,6 @@ More interesting features are yet to come. Stay tuned!
 
 ## Roadmap
 
- * Provide a way to create user-defined partition creation\destruction callbacks (issue [#22](https://github.com/postgrespro/pg_pathman/issues/22))
  * Implement LIST partitioning scheme;
  * Optimize hash join (both tables are partitioned by join key).
 

src/pathman.h

@@ -66,12 +66,12 @@
  */
 #define PATHMAN_PARTITION_LIST				"pathman_partition_list"
 #define Natts_pathman_partition_list		6
-#define Anum_pathman_pl_parent				1
-#define Anum_pathman_pl_partition			2
-#define Anum_pathman_pl_parttype			3
-#define Anum_pathman_pl_partattr			4
-#define Anum_pathman_pl_range_min			5
-#define Anum_pathman_pl_range_max			6
+#define Anum_pathman_pl_parent				1	/* partitioned relation (regclass) */
+#define Anum_pathman_pl_partition			2	/* child partition (regclass) */
+#define Anum_pathman_pl_parttype			3	/* partitioning type (1|2) */
+#define Anum_pathman_pl_partattr			4	/* partitioned column (text) */
+#define Anum_pathman_pl_range_min			5	/* partition's min value */
+#define Anum_pathman_pl_range_max			6	/* partition's max value */
 
 
 /*

src/pl_funcs.c

@@ -62,15 +62,18 @@ PG_FUNCTION_INFO_V1( invoke_on_partition_created_callback );
 PG_FUNCTION_INFO_V1( debug_capture );
 
 
+/*
+ * User context for function show_partition_list_internal().
+ */
 typedef struct
 {
 	Relation				pathman_config;
 	HeapScanDesc			pathman_config_scan;
 	Snapshot				snapshot;
 
-	const PartRelationInfo *current_prel;
+	const PartRelationInfo *current_prel;	/* selected PartRelationInfo */
 
-	uint32					child_number;
+	uint32					child_number;	/* child we're looking at */
 } show_partition_list_cxt;
 
 
@@ -348,6 +351,7 @@ show_partition_list_internal(PG_FUNCTION_ARGS)
 		/* Alias to 'usercxt->current_prel' */
 		prel = usercxt->current_prel;
 
+		/* If we've run out of partitions, switch to the next 'prel' */
 		if (usercxt->child_number >= PrelChildrenCount(prel))
 		{
 			usercxt->current_prel = NULL;
@@ -359,10 +363,12 @@ show_partition_list_internal(PG_FUNCTION_ARGS)
 		partattr_cstr = get_attname(PrelParentRelid(prel), prel->attnum);
 		if (!partattr_cstr)
 		{
+			/* Parent does not exist, go to the next 'prel' */
 			usercxt->current_prel = NULL;
 			continue;
 		}
 
+		/* Fill in common values */
 		values[Anum_pathman_pl_parent - 1]		= PrelParentRelid(prel);
 		values[Anum_pathman_pl_parttype - 1]	= prel->parttype;
 		values[Anum_pathman_pl_partattr - 1]	= CStringGetTextDatum(partattr_cstr);