Have encountered an intriguing issue processing a table with a large
number of rows. The process is to loop over the table processing each
row executing the Apache AGE cypher function over each row
individually.The looping is necessary because of encountering a limit on
the number of rows that the cypher function would process.
The process terminates unexpectedly with the following message. Notable
that it runs for quite some time before termination.:
SQL Error [42703]: ERROR: could not find rte for
a01a724103fbb3d059b8387bf043dbc8
Where: PL/pgSQL function
analysis.create_trips(text,text,text,text,text,text,integer,text,integer)
line 5 at EXECUTE
Of note the the string refers to a value in the field service_key.
The first instance of the service_key when ordered is in row 7741 shown
below.
*row_num* *service_key* *service_id* *trip_id* *trip_headsign*
*route_id* *direction_id* *shape_id* *wheelchair_accessible*
7741 a01a724103fbb3d059b8387bf043dbc8 FR 307 Gungahlin Pl X1 0
1002 1
The database version is PostgreSQL 15.4 (Debian 15.4-2.pgdg120+1) on
x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit.
The attributes of the table allservices.trips are as follows:
* Total size with indexes: 60 MB
* Number of rows: 231,131
This is the function definition and the process to load the table
allservices.trips into the Apache AGE graph schema.
Any assistance in refining the process to ensure completion welcome.
Regards
Matt.
SELECT create_graph('transport_network');
CREATE OR REPLACE FUNCTION analysis.create_trips
(graph_name text,
service_key text,service_id text, trip_id text, trip_headsign text,
route_id text, direction_id int, shape_id text, wheelchair_accessible int)
returns text
LANGUAGE plpgsql
VOLATILE
as $trips$
declare
nodename text := graph_name || '.' || 'trips';
BEGIN
execute
format ('select * from cypher(''%1$s'', $$match (v:routes {id: %6$s})
create(v)-[:USES]->
(t:trips
{service_key: %2$s, service_id: %3$s, id: %4$s, headsign: %5$s,
route_id: %6$s, direction_id: %7$s, shape_id: %8$s,
wheelchair_accessible: %9$s})$$) as (t agtype);',
quote_ident(graph_name),
quote_ident(service_key),quote_ident(service_id),
quote_ident(trip_id),quote_ident(trip_headsign),
quote_ident(route_id),to_char(direction_id,'9'),quote_ident(shape_id),to_char(wheelchair_accessible,'9'));
return nodename;
END
$trips$
;
select create_vlabel('transport_network','trips');
do $$
declare temprow record;
graph_name text:='transport_network';
counter integer := 0 ;
begin
for temprow in select service_key, service_id, trip_id from
allservices.trips
order by service_key,trip_id
loop
counter := counter+1; -- Prevent replication of row
perform
analysis.create_trips
(graph_name,
a.service_key, a.service_id,
a.trip_id, a.trip_headsign,
a.route_id, a.direction_id, a.shape_id,
a.wheelchair_accessible)
from
(select row_number() over (order by service_key,trip_id) as row_num,
service_key, service_id,
trip_id, trip_headsign,
route_id, direction_id, shape_id,
coalesce(wheelchair_accessible,0) as wheelchair_accessible from
allservices.trips) a
where a.row_num=counter
;
end loop;
end; $$;
