nikoraes opened a new issue, #2160:
URL: https://github.com/apache/age/issues/2160
Hi, I'm using Cloudnative PG with readonly replicas and I'm having issues
with VLE queries. I'm always getting the following error message on the standby
(replica server, even though I'm just doing a match query.
"message":"cannot acquire lock mode ShareLock on database objects while
recovery is in progress",
"hint":"Only RowExclusiveLock or less can be acquired on database objects
during recovery."
I tested like this:
connect to primary and run the following to create the graph (same as in
tests)
`SELECT * FROM cypher('cypher_vle', $$CREATE (b:begin)-[:edge {name: 'main
edge', number: 1, dangerous: {type: "all", level: "all"}}]->(u1:middle)-[:edge
{name: 'main edge', number: 2, dangerous: {type: "all", level: "all"},
packages: [2,4,6]}]->(u2:middle)-[:edge {name: 'main edge', number: 3,
dangerous: {type: "all", level: "all"}}]->(u3:middle)-[:edge {name: 'main
edge', number: 4, dangerous: {type: "all", level: "all"}}]->(e:end),
(u1)-[:self_loop {name: 'self loop', number: 1, dangerous: {type: "all", level:
"all"}}]->(u1), (e)-[:self_loop {name: 'self loop', number: 2, dangerous:
{type: "all", level: "all"}}]->(e), (b)-[:alternate_edge {name: 'alternate
edge', number: 1, packages: [2,4,6], dangerous: {type: "poisons", level:
"all"}}]->(u1), (u2)-[:alternate_edge {name: 'alternate edge', number: 2,
packages: [2,4,6], dangerous: {type: "poisons", level: "all"}}]->(u3),
(u3)-[:alternate_edge {name: 'alternate edge', number: 3, packages: [2,4,6],
dangerous: {type: "poisons", lev
el: "all"}}]->(e), (u2)-[:bypass_edge {name: 'bypass edge', number: 1,
packages: [1,3,5,7]}]->(e), (e)-[:alternate_edge {name: 'backup edge', number:
1, packages: [1,3,5,7]}]->(u3), (u3)-[:alternate_edge {name: 'backup edge',
number: 2, packages: [1,3,5,7]}]->(u2), (u2)-[:bypass_edge {name: 'bypass
edge', number: 2, packages: [1,3,5,7], dangerous: {type: "poisons", level:
"all"}}]->(b) RETURN b, e $$) AS (b agtype, e agtype);
`
Then run this query
`SELECT * FROM cypher('cypher_vle', $$MATCH (u:begin)-[*]->(v:end) RETURN
count(*) $$) AS (e agtype);`
This query return 400 on the primary server.
Then I connect to the standby server (replica) and run the same query. This
now returns the error about the ShareLock.
The following queries do work
`SELECT * FROM cypher('cypher_vle', $$MATCH (u:begin)-[]->(v:middle) RETURN
count(*) $$) AS (e agtype); // returns 2`
`SELECT * FROM cypher('cypher_vle', $$MATCH (u:middle)-[]->(v:end) RETURN
count(*) $$) AS (e agtype); // returns 3`
Are there any workaround do make VLE queries work on read-only replicas?
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