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--
-- XC_CREATE_FUNCTIONS
--
-- Create a couple of functions used by Postgres-XL tests
-- A function to create table on specified nodes
create or replace function create_table_nodes(tab_schema varchar, nodenums int[], distribution varchar, cmd_suffix varchar)
returns void language plpgsql as $$
declare
cr_command varchar;
nodes varchar[];
nodename varchar;
nodenames_query varchar;
nodenames varchar;
node int;
sep varchar;
tmp_node int;
num_nodes int;
begin
nodenames_query := 'SELECT node_name FROM pgxc_node WHERE node_type = ''D''';
cr_command := 'CREATE TABLE ' || tab_schema || ' DISTRIBUTE BY ' || distribution || ' TO NODE ';
for nodename in execute nodenames_query loop
nodes := array_append(nodes, nodename);
end loop;
nodenames := '(';
sep := '';
num_nodes := array_length(nodes, 1);
foreach node in array nodenums loop
tmp_node := node;
if (tmp_node < 1 or tmp_node > num_nodes) then
tmp_node := tmp_node % num_nodes;
if (tmp_node < 1) then
tmp_node := num_nodes;
end if;
end if;
nodenames := nodenames || sep || nodes[tmp_node];
sep := ', ';
end loop;
nodenames := nodenames || ')';
cr_command := cr_command || nodenames;
if (cmd_suffix is not null) then
cr_command := cr_command || ' ' || cmd_suffix;
end if;
execute cr_command;
end;
$$;
-- Add/Delete/change node list of a table
CREATE OR REPLACE FUNCTION alter_table_change_nodes(tab_schema varchar, nodenums int[], command varchar, distribution varchar)
RETURNS BOOLEAN LANGUAGE plpgsql as $$
declare
cr_command varchar;
nodes varchar[];
nodename varchar;
nodenames_query varchar;
nodenames varchar;
sep varchar;
nodenum_new int[];
nodenum_res int[];
tmp_node int;
num_nodes int;
node int;
check_num boolean;
enforce_to boolean;
BEGIN
-- Check the command type, only delete/add/to are allowed
IF command != 'delete' AND command != 'add' AND command != 'to' THEN
RETURN FALSE;
END IF;
nodenames_query := 'SELECT node_name FROM pgxc_node WHERE node_type = ''D''';
FOR nodename IN EXECUTE nodenames_query LOOP
nodes := array_append(nodes, nodename);
END LOOP;
nodenames := '(';
sep := '';
num_nodes := array_length(nodes, 1);
enforce_to := FALSE;
-- Adjust node array according to total number of nodes
FOREACH node IN ARRAY nodenums LOOP
tmp_node := node;
IF (node < 1 OR node > num_nodes) THEN
-- Enforce the usage of TO here, only safe method
enforce_to := TRUE;
tmp_node := node % num_nodes;
nodenum_new := array_append(nodenum_new, tmp_node);
END IF;
nodenum_new := array_append(nodenum_new, tmp_node);
END LOOP;
-- Eliminate duplicates
nodenum_res := array_append(nodenum_res, nodenum_new[1]);
FOREACH node IN ARRAY nodenum_new LOOP
check_num := TRUE;
FOREACH tmp_node IN ARRAY nodenum_res LOOP
IF (tmp_node = node) THEN
check_num := FALSE;
END IF;
END LOOP;
-- Fill in result array only if not replicated
IF check_num THEN
nodenum_res := array_append(nodenum_res, node);
END IF;
END LOOP;
-- If there is a unique Datanode in cluster, enforce the use of 'TO NODE'
-- This will avoid any consistency problems
IF (num_nodes = 1 OR enforce_to) THEN
command := 'TO';
END IF;
-- Finally build query
cr_command := 'ALTER TABLE ' || tab_schema || ' ' || command || ' NODE ';
FOREACH node IN ARRAY nodenum_res LOOP
IF (node > 0 AND node <= num_nodes) THEN
nodenames := nodenames || sep || nodes[node];
sep := ', ';
END IF;
END LOOP;
nodenames := nodenames || ')';
cr_command := cr_command || nodenames;
-- Add distribution if necessary
IF (distribution IS NOT NULL) then
cr_command := cr_command || ', DISTRIBUTE BY ' || distribution;
END IF;
-- Launch it
EXECUTE cr_command;
RETURN TRUE;
END;
$$;
-- A function to return data node name given a node number
CREATE OR REPLACE FUNCTION get_xc_node_name(node_num int) RETURNS varchar LANGUAGE plpgsql AS $$
DECLARE
r pgxc_node%rowtype;
node int;
nodenames_query varchar;
BEGIN
nodenames_query := 'SELECT * FROM pgxc_node WHERE node_type = ''D'' ORDER BY xc_node_id';
node := 1;
FOR r IN EXECUTE nodenames_query LOOP
IF node = node_num THEN
RETURN r.node_name;
END IF;
node := node + 1;
END LOOP;
RETURN 'NODE_?';
END;
$$;
-- A function to check whether a certain transaction was prepared on a specific data node given its number
CREATE OR REPLACE FUNCTION is_prepared_on_node(txn_id varchar, nodenum int) RETURNS bool LANGUAGE plpgsql AS $$
DECLARE
nodename varchar;
qry varchar;
r pg_prepared_xacts%rowtype;
BEGIN
nodename := (SELECT get_xc_node_name(nodenum));
qry := 'EXECUTE DIRECT ON (' || nodename || ') ' || chr(39) || 'SELECT * FROM pg_prepared_xacts' || chr(39);
FOR r IN EXECUTE qry LOOP
IF r.gid = txn_id THEN
RETURN true;
END IF;
END LOOP;
RETURN false;
END;
$$;
-- A function to execute direct a query on a data node specified by the node number.
create or replace function exec_util_on_node(query varchar, nodenum int) returns void as
$D$
DECLARE
str varchar;
node_name varchar;
BEGIN
node_name = get_xc_node_name(nodenum);
str = 'execute direct on (' || node_name || ') $$ ' || query || ' $$' ;
execute str;
END $D$ language plpgsql;
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