On 17/02/18 12:37, Fabien COELHO wrote:
Why not then insert a "few" rows, measure size, truncate the
table, compute the formula and then insert to the desired user
requested size? (or insert what should be the minimum, scale 1,
measure, and extrapolate what's missing). It doesn't sound too
complicated to me, and targeting a size is
something that I believe it's quite good for user.
The formula I used approximates the whole database, not just one
table. There was one for the table, but this is only part of the
issue. In particular, ISTM that index sizes should be included when
caching is considered.
Also, index sizes are probably in n ln(n), so some level of
approximation is inevitable.
Moreover, the intrinsic granularity of TPC-B as multiple of 100,000
rows makes it not very precise wrt size anyway.
Sure, makes sense, so my second suggestion seems more reasonable:
insert with scale 1, measure there (ok, you might need to crete indexes
only to later drop them), and if computed scale > 1 then insert whatever
is left to insert. Shouldn't be a big deal to me.
I like the feature :)
Álvaro
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Alvaro Hernandez
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OnGres
