More optimal way of deleting partitions

Author: knizhnik

src/pg_shardman.c

@@ -761,16 +761,6 @@ node_in_cluster(int id)
 	return res;
 }
 
-static void
-rm_partition(int node_id, char const* part_name)
-{
-	char* sql;
-	sql = psprintf("delete from shardman.partitions where owner=%d and part_name='%s'",
-				   node_id, part_name);
-	void_spi(sql);
-	pfree(sql);
-}
-
 /*
  * Remove node, losing all data on it. We
  * - ensure that there is active node with given id in the cluster
@@ -787,7 +777,7 @@ rm_node(Cmd *cmd)
 	char *sql;
 	char **opts;
 	bool force = false;
-	int i, e;
+	int e;
 
 	for (opts = cmd->opts; *opts; opts++)
 	{
@@ -799,28 +789,26 @@ rm_node(Cmd *cmd)
 	}
 
 	SPI_PROLOG;
-	sql = psprintf("select part_name from shardman.partitions where owner=%d", node_id);
-	e = SPI_execute(sql, true, 0);
-	if (e < 0)
-		shmn_elog(FATAL, "Stmt failed: %s", sql);
-	pfree(sql);
-	if (SPI_processed > 0)
+	if (force)
 	{
-		TupleDesc rowdesc = SPI_tuptable->tupdesc;
-		if (!force)
+		sql = psprintf("delete from shardman.partitions where owner=%d", node_id);
+		void_spi(sql);
+	}
+	else
+	{
+		bool isnull;
+		sql = psprintf("select count(*) from shardman.partitions where owner=%d", node_id);
+		e = SPI_execute(sql, true, 0);
+		if (e < 0)
+			shmn_elog(FATAL, "Stmt failed: %s", sql);
+		Assert(SPI_processed == 1);
+		if (DatumGetInt64(SPI_getbinval(SPI_tuptable->vals[0], SPI_tuptable->tupdesc, 1, &isnull)) != 0)
 		{
-
 			ereport(ERROR, (errmsg("Can not remove node with existed partitions"),
 							errhint("Add \"force\" option to remove node with existed partitions.")));
 		}
-		/* Remove partitions belonging to this node */
-		for (i = 0; i < SPI_processed; i++)
-		{
-			HeapTuple tuple = SPI_tuptable->vals[i];
-			char const* partition = SPI_getvalue(tuple, rowdesc, 1);
-			rm_partition(node_id, partition);
-		}
 	}
+	pfree(sql);
 	SPI_EPILOG;
 
 	elog(INFO, "Removing node %d ", node_id);