Re: Extents and next extent size

Graeme Muirhead wrote: > > I am trying to find out (a) if there are guidelines for specifying the next > extent size, based on , for example, the number of rows in a table or the Yes many guidelines as a matter of fact. Some of us use a formula like NextSize = ExtentSize * N% NextSize = approx 1-year's growth NextSize = approx 1-month growth etc etc etc This is why myschema.ec has several optional ways of generating NEXT SIZE in the schema's it outputs. The formula that you settle on, and you may use different ones for different tables, will depend on the nature of your data, the way in which it is queries and updated, your disk layout, table size, and many other factors. An example I gave just this week is a table that is seldom deleted from and most queries are against the current quarter's data except for the monthly history comparisons and annual summaries. In this case NEXT SIZE should be large enough to contain a quarter's worth of data in a single extent so only one or two extents are normally accessed. > rate at which rows are added (b) where the NEXT SIZE value is stored - > presumably somewhere in the sysmaster database? It is indeed stored in the sysptnhdr table in sysmaster but it is also in the systables record for the table. In either case the column is nextsize. Art S. Kagel