Dear Gunnar, > postgres=# CREATE TABLE test (i int, lz4 text COMPRESSION lz4, std text); > postgres=# INSERT INTO test SELECT > i,repeat(md5(i::text),100),repeat(md5(i::text),100) FROM > generate_series(0,100000) x(i); > postgres=# SELECT * FROM pg_stat_toast WHERE schemaname = 'public'; > -[ RECORD 1 ]--------+---------- > schemaname | public > reloid | 16829 > attnum | 2 > relname | test > attname | lz4 > externalizations | 0 > compressions | 100001 > compressionsuccesses | 100001 > compressionsizesum | 6299710 > originalsizesum | 320403204 > -[ RECORD 2 ]--------+---------- > schemaname | public > reloid | 16829 > attnum | 3 > relname | test > attname | std > externalizations | 0 > compressions | 100001 > compressionsuccesses | 100001 > compressionsizesum | 8198819 > originalsizesum | 320403204
I'm not sure about TOAST, but currently compressions are configurable: https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=bbe0a81db69bd10bd166907c3701492a29aca294 How about adding a new attribute "method" to pg_stat_toast? ToastAttrInfo *attr->tai_compression represents how compress the data, so I think it's easy to add. Or, is it not needed because pg_attr has information? Best Regards, Hayato Kuroda FUJITSU LIMITED
