Update statistics made query 2-3x slower

[Ciureanu, Constantin (GfK)]

Hello all,


1.     Is there a good explanation why updating the statistics:
update statistics tableX;

made this query 2x times slower?   (it was 27 seconds before, now it’s 
somewhere between 60 – 90 seconds)
select count(*) from tableX;
+------------------------------------------+
|                 COUNT(1)                 |
+------------------------------------------+
| 5786227                                  |
+------------------------------------------+
1 row selected (62.718 seconds)

(If possible ☺ ) how can I “drop” those statistics?

2. Why there is nothing (like a counter / attribute for the table) to obtain 
the number of rows in one table fast?

Thank you,
   Constantin