Hi all, I've a doubt about running ANALYZE and inspecting pg_class.xmin and pg_class.reltuples. Let's create a simple table (note, I'm the only user on this instance): testdb=> CREATE TABLE fizz AS SELECT v FROM generate_series( 1, 100 ) v; SELECT 100 testdb=> SELECT relpages, reltuples, xmin, age( xmin ) FROM pg_class WHERE relname = 'fizz'; -[ RECORD 1 ]--------- relpages | 0 reltuples | 0 xmin | 2359180435 age | 1 Therefore transaction 435 created the table. Now analyze the table: testdb=> analyze fizz; ANALYZE testdb=> SELECT relpages, reltuples, xmin, age( xmin ) FROM pg_class WHERE relname = 'fizz'; -[ RECORD 1 ]--------- relpages | 1 reltuples | 100 xmin | 2359180435 age | 2 So the pg_class record has changed its content, and in fact we are now 2 transaction away the table creation, but the pg_class.xmin is the same. I would have expected that pg_class.xmin was updated as per user-tables.Now, clearly ANALYZE hit the pg_statistic table and the xmin "update" is there, but this would make me thing pg_class.reltuples is a generated column based on some aggregation of the latter pg_statistic, that apparently is not. Am I missing something? Thanks, Luca
