Why does DESCRIBE EXTENDED in Kafka KSQL return error ShowColumns not supported? - apache-kafka

Question

I have a simple KTABLE in KSQL called DIMAGE
When I run the following code
{
"ksql": "DESCRIBE EXTENDED DIMAGE ;"
}
I receive the following error
{
"#type": "generic_error",
"error_code": 40000,
"message": "Statement type `io.confluent.ksql.parser.tree.ShowColumns' not supported for this resource",
"stackTrace": []
}
I also receive a similar error message trying to describe a stream. I also receive the same error message if I remove the EXTENDED attribute.

Answer 1

You're using the wrong REST endpoint. If you use query endpoint query you'll get your error:
$ curl -s -X "POST" "http://localhost:8088/query" \
-H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
-d '{
"ksql": "DESCRIBE EXTENDED COMPUTER_T;"
}'
{"#type":"generic_error","error_code":40000,"message":"Statement type `io.confluent.ksql.parser.tree.ShowColumns' not supported for this resource","stackTrace":[]}⏎
If you use the statement endpoint ksql it works fine:
$ curl -s -X "POST" "http://localhost:8088/ksql" \
-H "Content-Type: application/vnd.ksql.v1+json; charset=utf-8" \
-d '{
"ksql": "DESCRIBE EXTENDED COMPUTER_T;"
}'|jq '.'
[
{
"#type": "sourceDescription",
"statementText": "DESCRIBE EXTENDED COMPUTER_T;",
"sourceDescription": {
"name": "COMPUTER_T",
"readQueries": [
{
"sinks": [
"COMP_WATCH_BY_EMP_ID_T"
],
"id": "CTAS_COMP_WATCH_BY_EMP_ID_T_0",
[...]
I've logged #2362 so that we can improve the UX of this.