On Sat, Nov 19, 2011 at 12:53 PM, Gavin Flower <GavinFlower@xxxxxxxxxxxxxxxxx> wrote: > On 19/11/11 11:32, Adam Cornett wrote: > > On Fri, Nov 18, 2011 at 2:56 PM, Gavin Flower > <GavinFlower@xxxxxxxxxxxxxxxxx> wrote: >> >> On 18/11/11 04:59, Tom Lane wrote: >>> >>> Craig Ringer<ringerc@xxxxxxxxxxxxx> writes: >>>> >>>> On Nov 17, 2011 1:32 PM, "Tom Lane"<tgl@xxxxxxxxxxxxx> wrote: >>>>> >>>>> If it's purely an insert-only table, such as a logging table, then in >>>>> principle you only need periodic ANALYZEs and not any VACUUMs. >>>> >>>> Won't a VACUUM FREEZE (or autovac equivalent) be necessary eventually, >>>> to >>>> handle xid wraparound? >>> >>> Sure, but if he's continually adding new rows, I don't see much point in >>> launching extra freeze operations. >>> >>> regards, tom lane >>> >> Just curious... >> >> Will the pattern of inserts be at all relevant? >> >> For example random inserts compared to apending records. I thought that >> random inserts would lead to bloat, as there would be lots of blocks far >> from the optimum fill factor. >> >> >> Regards, >> Gavin >> >> -- >> Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) >> To make changes to your subscription: >> http://www.postgresql.org/mailpref/pgsql-general > > I might be wrong (I'm sure Tom will correct me if so), but Postgres does not > store tuples in an ordered format on disk, they are on disk in the order > they are inserted, unless the table is re-ordered by cluster, which only > does a one time sort. > Table bloat (and the table fill factor) are usually associated with deletes > and updates. If you delete a row, or update it so that it takes up less > room (by say removing a large text value) then postgres could use the now > free space on that page to store a new tuple. > -Adam > > HI Adam, > > I suspect that you are right - noiw I come to think of it- I think I got > caught out by the ghost of VSAM creeping up on me )You seriously do NOT want > to know about IBM's VSAM!). Careful, on a list with as many old timers as this one, you may be sending that message to the guy who wrote the original implementation. :) I only go as far back as Rexx and JCL and RBase 5000, but never used VSAM. ISAM yes. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
