Fulltext CONTAINSTABLE predicate push down - wrong statistics

Question

Hi, 
We use the CONTAINSTABLE function to search the fulltext index in our production environment. 
We use the strategy, described in this article http://support.microsoft.com/kb/2549443
This is part of our query. The query is mixed with relational and fulltext predicates: 
df.DOCUMENT_TEXTS_TMP doctext ON doc.DOC_ID = doctext.DOC_ID
INNER JOIN containstable(df.DOCUMENT_TEXTS_TMP, ABOUT, @p_about) r ON doctext.ID = r.[KEY] AND r.[KEY] BETWEEN @p_From_ID AND @p_To_ID
This is part  of the SCHEMA: 
CREATE TABLE [df].[DOCUMENT_TEXTS_TMP](
[DOC_ID] [bigint] NOT NULL,
[ABOUT] [nvarchar](1000) NOT NULL,
[REMARK] [nvarchar](4000) NULL,
[REGISTRATION_DATE] [datetime] NULL,
[ID] [bigint] NOT NULL)
We encode the REGISTRATION_DATE and the DOC_ID into the ID column with this function: 
DATEDIFF(DAY, '19000101', REGISTRATION_DATE]) * 100000000000000 + DOC_ID
We use the ID column as a key for the full text index.
When we search with the predicate "AND r.[KEY] BETWEEN @p_From_ID AND @p_To_ID" the estimated number of rows returned from the containstable function is roughly 10 percent of the total number of rows without that predicate. This is true ONLY
when we use wildcard for the @p_about parameter: like this - @p_about = N'"Jhon*"'. When we remove the wildcard ('"Jhon"') then the estimations are ok ! 
When we search without the "AND r.[KEY] BETWEEN @p_From_ID AND @p_To_ID" predicate, then the estimated number of rows returned from the containstable function are very good independently from the wildcard in the @p_about param.
We reached the 10% number with many samples. It is not exact percent, but it is roughly there.
Because of this, there are situations in which wrong query plans are generated and the performance is very poor.
Is there a specific reason for this behaviour or maybe we do something wrong ?
Thank you in advance,
Atanas

Answer 1

this is the first I have heard of that parameter...
TASD:
SQL> show
parameter optimizer_secure
NAME                               
TYPE    VALUE
optimizer_secure_view_merging                 boolean      TRUE
So what affect does it have on what I'm seeing???
Thanks so much for the help!
Cory