I have a fairly basic question: what is the best choice of indices for a
table? In practice, I have a table with 20+ million rows and about 25
columns. Some are very fine-grained (integers on the order of 10^8 for a
range) and some are much less (6 values over the 20M rows). Are there
general rules for what and in what combinations to index (besides index
columns that are going to be looked up often)? Any good links?
Thanks and sorry for the vague, ill-formed questions.
Sean