Hi, I have a tree-structure managed with ltree and gist index. Simplified schema is CREATE TABLE crt ( idcrt INT NOT NULL, ... pathname LTREE ) idcrt primary key and other index ix_crt_pathname on pathname with gist CREATE TABLE doc ( iddoc INT NOT NULL, ...) iddoc primary key CREATE TABLE folder_document ( id_folder int not null, id_document int not null, ... path_folder ltree not null ); id_folder , id_document are primary key ix_folder_document_path_folder on path_folder with gist when enable_bitmapscan is set on query go on 1000 seconds, when I turned off bitmapscan query go on 36 seconds. I've noticed query use all buffer with ix_folder_document_path_folder, using contrib pg_buffercache. Table crt have about 1.3 milion row folder_document 15 milion row and doc about 8 milion row. Query plan with enable_bitmapscan = ON is http://explain.depesz.com/s/d97 Query plan with enable_bitmapscan = OFF is http://explain.depesz.com/s/wgp All query are execute after reboot machine. other parameter set shared_buffer = 1GB work_mem = 128MB maintenance_work_mem = 512MB effective_cache_size = 1GB I've test same query on PostgreSQL 9.1.5 and query go ok with enable_bitmapscan = on. I see in release note 9.0.5 "Fix performance problem when constructing a large, lossy bitmap", is same problem with 9.0.10? My enviroment Linux OpenSUSE 12.2 x64 PostgreSQL release 9.0.10 compiled from source PostgreSQL release 9.1.5 from official repository Processor Intel Core i5 2.8GHz and 8GB RAM -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
