Workarounds to fix HTTP OLAP not functioning

[Peter Ryall]

I've noticed a few people trying to get HTTP OLAP working
without success. I had the same problem and hope I can
shed some light. Note that direct OLAP connections worked
all along just HTTP failed.

After debugging the msolap.asp file I have determined two
things than can kill it.

Firstly, Session State must be enabled for the virtual app
it is running in. This sounds obvious as the page uses
Session("SessionPump"). However, the audience is SQL
admins not IIS developers. Symptoms of this include high
CPU utilization on both inetinfo.exe and dllhost.exe as
there are hundreds of calls to the page as the OLAP
provider keeps trying. To fix goto Properties (for the
virtual directory) -> Directory -> Configuration -> App
Options -> Enable Session State in the Internet Services
Manager.

Problem number 2 is buffering. Change the
<%Response.Buffer=FALSE%> to <%Response.Buffer=TRUE%> and
this is fixed. Symptom of this is dllhost.exe with high
CPU. Don't ask me why <%Response.Buffer=FALSE%> and
Response.Flush are on the same page in the first place.

Hope someone in PSS sees this and writes a KB article,
because this took a while for me to pin down.