Achilleus ,
> performance for the following problem:
> I want to store the factors of a linear formula of unknown degree
> (but less
> than 10) in a table for online stats/graphs on historical data (about
> 200 Mb).
> I am thinking of
> a) Store each formula as a float8[] array and then write a pgsql
> function in C
> to compute the result given the value of variable x.
> b) Add 10 columns of type float8 and store 0 values where the
> position of the
> column exceeds the degree of the formula.
BOTH of the above are poor approaches that will lead to headaches foryou later on. Instead:
c. Store each formula in a column in another table with a parent-childrelationship to your main table, i.e.
online_stats stat_formulas
--------------- ------------------
online_stat_id ------------->online_stat_id formula_number
formula
This is basic relational database design. You should probably pick upa copy of "Relational Database Design for Mere
Mortals" before youget yourself into a real mess ...
-Josh Berkus