create table idxpart (a int) partition by range (a);create index on idxpart (a);

WARNING: Current PostgreSQL role is superuser. It is not recommended to run backup or checkdb as superuser.INFO: Start checking data filesINFO: Data files are validWARNING: Current PostgreSQL role is superuser. It is not recommended to run backup or checkdb as superuser.INFO: Start amchecking PostgreSQL instanceINFO: Amchecking database 'postgres' using extension 'amcheck' version 1.3 from schema 'public'WARNING: Thread [1]. Amcheck failed in database 'postgres' for index: 'public.idxpart_a_idx': ERROR:  only B-Tree indexes are supported as targets for verificationDETAIL:  Relation "idxpart_a_idx" is not a B-Tree index.WARNING: Thread [1]. Amcheck failed in database 'postgres' for index: 'public.idxpart_a_idx1': ERROR:  only B-Tree indexes are supported as targets for verificationDETAIL:  Relation "idxpart_a_idx1" is not a B-Tree index.WARNING: Amcheck failed for database 'postgres'ERROR: checkdb --amcheck finished with failure. Not all checked indexes are valid. All databases were amchecked.1