"SEE TABLE SCHEMA" queries to trino never finish

[maxgruber19]

We found a very ugly issue when connecting superset to trino. A user has reported that superset is very slow and no query is processed sometimes. We found out that superset does not finish its queries when somebody selects a table (iceberg) in the "SEE TABLE SCHEMA" dropdown. Combined with our resource pools (users can submit only 5 queries at a time, 6th will be queued) that's definitely a customer facing problem for us.

3 Queries to trino are fired from superset which are all the same

SELECT * FROM default."tablename$partitions"

Superset already gets a result after couple of seconds and displays the table schema but the query stays in state "FINISHING" until a timeout of ~5mins is hit. The query then is abandoned by trino itself.

io.trino.spi.TrinoException: Query 20250828_082847_00409_ksycd was abandoned by the client, as it may have exited or stopped checking for query results. Query results have not been accessed since 2025-08-28T08:28:49.874Z: currentTime 2025-08-28T08:33:50.786Z
	at io.trino.execution.QueryTracker.failAbandonedQueries(QueryTracker.java:275)
	at io.trino.execution.QueryTracker.lambda$start$0(QueryTracker.java:83)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
	at java.base/java.util.concurrent.FutureTask.runAndReset(Unknown Source)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)

Do you have an idea what to do? Maybe you know that already?

Edit: The tables have a bigger amount of partitions, we didn't manage to optimize them yet. Some of the tables have ~10.000 partitions (they are streaming destinations partitioned by processing-time for a spark application with 10min batches). Maybe that's relevant, but I don't think so because superset displays the schema just in time - it feels like just a thing of non terminating queries. According to trino superset fetches ~10000 rows and 5mb from those queries.

We are running superset:4.0.2-stackable25.3.0 and trino:451-stackable24.11.0 in that environment

[sbernauer]

Hi Max!
I tried reproducing this (im on SDP 25.7 with Trino 476 and Superset 4.1.2)

For the table

create table iceberg.tpch.nation as select * from tpch.sf1.nation;

I get

The queries Superset runs on Trino are:

1. list partitions, works

SELECT * FROM tpch."nation_part$partitions"

2. Some other random queries, works

3. This weird thing, fails with Column 'record_count' cannot be resolved

SELECT
  *
FROM tpch.nation
WHERE
  record_count = 25
  AND file_count = 1
  AND total_size = 1897
  AND data = '[[0, 24, 0, null], ["ALGERIA", "VIETNAM", 0, null], [0, 4, 0, null], [" haggle. careful", "y final packaget", 0, null]]'
LIMIT 101

For the table

create table iceberg.tpch.nation_part with (partitioning = ARRAY['name']) as select * from tpch.sf1.nation;

I get the exact same result, most queries passing, but this "nice" one fails with Column 'partition' cannot be resolved:

SELECT
  *
FROM tpch.nation_part
WHERE
  partition = '["VIETNAM"]'
  AND record_count = 1
  AND file_count = 1
  AND total_size = 886
  AND data = '[[21, 21, 0, null], [2, 2, 0, null], ["hely enticingly ", "hely enticingly!", 0, null]]'
LIMIT 101

But I never get a stuck query, the table schema view seems to work, but the Data preview is broken.
But honestly I'm used to this thing being broken.

Upstream issues at Superset for this bug are

apache/superset#26449
apache/superset#25307
apache/superset#31881

I assume your problem here is with the number of partitions. So likely Superset runs into a timeout and stops polling the query, but does not cancel it properly.
You might be able to reduce query.client.timeout to e.g. a minute to reduce the impact. Other Trino clients should hopefully poll quick enough.
Other than that I sadly can't recommend any workaround.

[maxgruber19]

Yeah I've seen that partition.. cannot be resolved thing since day one and my workaround was to disable preview queries in the specific database connection on superset side.

Sad thing that you don't have a workaround. I'll test around the thing with the too much partitions of the table, maybe I can find something further. I'll leave that issue open for my further investigation

[sbernauer]

On thing I prepared, that might help with debugging what exactly is going wrong is stackabletech/documentation#780.
There is a rendered preview in https://deploy-preview-780--stackable-docs.netlify.app/home/nightly/guides/debug-network-traffic/.
You could try analyzing the HTTP stream to see what response Superset gets and when it stops polling