Hi, Here is the execution of a script for a cluster where checksums are enabled. The script could be more simple. However, I simplified it compared to my original script. This is version and platform information (System is CentOS Stream release 8) cours=# select version(); version -------------------------------------------------------------------------------------------------------- PostgreSQL 14.2 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-4), 64-bit (1 ligne) First the creation of the table: \set ECHO all \set jours 1000 drop table if exists test cascade; DROP TABLE create table test ( seq bigint, date_op timestamp, valeur real ); CREATE TABLE select setseed(0.5); setseed --------- (1 ligne) insert into test (seq, date_op, valeur) select seq, current_timestamp - interval :'jours' day + make_interval(mins => seq) date_op, 100 * random() valeur from generate_series(0, :jours * 24 * 60 - 1) seq; INSERT 0 1440000 alter table test add constraint pk_test primary key (seq); ALTER TABLE Now we will corrupt storage file of table test using ‘dd’ \set ECHO all show data_checksums; data_checksums ---------------- on (1 ligne) select current_setting('data_directory') || '/' || pg_relation_filepath('test') file_path; file_path ----------------------------------------------------------- /pgsql/pgdata/pg_tblspc/16384/PG_14_202107181/16386/16444 (1 ligne) \gset \setenv file_path :file_path \! dd if=/dev/zero of=$file_path bs=1024 count=100 100+0 enregistrements lus 100+0 enregistrements écrits 102400 octets (102 kB, 100 KiB) copiés, 0,000910942 s, 112 MB/s select count(*) from test; count ------- 1884 (1 ligne) Well, I think this is cache in action. If server is restarted, then the reply is 0. That is despite the deliberate choice of non 8KB multiplier size. PostgreSQL doesn’t complain during ordinary operations. Complaints come when we try to play with checksums using pg_checksums. select count(*) from test; count ------- 0 (1 ligne) I consider this is a serious problem. Best regards Michel SALAIS |
