On 2018-Aug-02, Thomas Munro wrote: > PostgreSQL only requires atomic writes of 512 bytes (see > PG_CONTROL_MAX_SAFE_SIZE), the traditional sector size for disks made > approximately 1980-2010, though as far as I know spinning disks made > this decade use 4KB sectors, and for SSDs there is more variation. I > suppose the theory for torn SLRU page safety today is that the > existing SLRU users all have fully independent values that don't cross > sector boundaries, so torn writes can't corrupt them.
Hmm, I wonder if this is true for multixact/members. I think it's not true for either 4kB sectors nor for 512 byte sectors. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
