Re: Plan time Improvement - 64bit bitmapset

Robert Haas <robertmhaas@gmail.com> wrote: 
> When you say, "don't fit in cache", exactly what
> cache are you talking about?  It seems to me that the statistics
> should be far smaller than the underlying tables, so if even your
> statistics don't fit in shared buffers (let alone main memory), it
> doesn't really matter how long your query takes to plan because it
> will probably take literally forever to execute.  How many tables
> would you have to be joining to get a GB of statistics, even with
> dst = 1000?  A few hundred?
Since he can't share the schema, and hasn't even given much of a hint,
I don't know whether one (or more) of the columns is a bytea filled
with 100 MB values; and I don't remember any description of the
hardware environment either.  Since the behavior seems so
out-of-the-ordinary, I was casting about for possible extraordinary
characteristics of his environment which might cause it.  I'm probably
way off base....
-Kevin