Does truncate and API Load invalidate statistics

As part of my data warehouse nightly build, I truncate my tables in my
target database.
As example, I find it is much quicker to do a bulk API load of 13M
records and to do an update/insert of 100K rows. I also drop the
indexes before the builds and reindex after. Thats an aside.
What I am wondering is how is this impacting the statistics? Do I need
to update them?
Not well versed on statistics and any data is welcomed.
Thanks
Robrcamarda (robc390@.hotmail.com) writes:

Quote:

Originally Posted by

As part of my data warehouse nightly build, I truncate my tables in my
target database.
As example, I find it is much quicker to do a bulk API load of 13M
records and to do an update/insert of 100K rows. I also drop the
indexes before the builds and reindex after. Thats an aside.
What I am wondering is how is this impacting the statistics? Do I need
to update them?

When an indexes added, statistics based a full scan is added for that
index, so you are fairly safe.

Would could matter is statistics of non-indexed columns. These you lose
when you truncate the tables. These statistics are less essential than
index on indexed columns, but there are queries where they may be useful.

--
Erland Sommarskog, SQL Server MVP, esquel@.sommarskog.se
Books Online for SQL Server 2005 at
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