jian xu <jamesxu@xxxxxxxxxxx> writes: > I tried to create gist index on a ltree column, first I got error > ERROR: stack depth limit exceeded Hm. What PG version is this? If it's up-to-date, can you provide some sample data that causes such problems? > one thing I notice is, there are some rows with many levels(more than 1k levels) in the ltree, if I delete those rows, creating gist index works I tried to reproduce this using just that information, but all I got was regression=# create table t (f1 ltree); CREATE TABLE regression=# create index on t using gist(f1); CREATE INDEX regression=# insert into t select ('0.' || (select string_agg(g::text,'.') from generate_series(1,100) g))::ltree; INSERT 0 1 regression=# insert into t select ('0.' || (select string_agg(g::text,'.') from generate_series(1,1000) g))::ltree; ERROR: index row requires 16048 bytes, maximum size is 8191 which is perhaps an annoying limitation, but it's not a bug. (I'm kind of wondering about the use-case for such long ltrees, anyway.) regards, tom lane