Michael Riess wrote: > hi, > > I'm curious as to why autovacuum is not designed to do full vacuum. Because a VACUUM FULL is too invasive. Lazy vacuum is so light on the system w.r.t. locks that it's generally not a problem to start one at any time. On the contrary, vacuum full could be a disaster on some situations. What's more, in general a lazy vacuum is enough to keep the dead space within manageability, given a good autovacuum configuration and good FSM configuration, so there's mostly no need for full vacuum. (This is the theory at least.) For the situations where there is a need, we tell you to issue it manually. > So my question is: What's the use of an autovacuum daemon if I still > have to use a cron job to do full vacuums? wouldn't it just be a minor > job to enhance autovacuum to be able to perform full vacuums, if one > really wants it to do that - even if some developers think that it's the > wrong approach? Yes, it is a minor job to "enhance" it to perform vacuum full. The problem is having a good approach to determining _when_ to issue a full vacuum, and having a way to completely disallow it. If you want to do the development work, be my guest (but let us know your design first). If you don't, I guess you would have to wait until it comes high enough on someone's to-do list, maybe because you convinced him (or her, but we don't have Postgres-ladies at the moment AFAIK) monetarily or something. You can, of course, produce a patch and use it internally. This is free software, remember. -- Alvaro Herrera Developer, http://www.PostgreSQL.org "God is real, unless declared as int"
