OBIEE Dashboards On Exalytics Fail With Error:" [nQSError: 16002] Cannot obtain number of columns for the query result... " If Running TimesTen Aggregate Refresh Simultaneously

Asset ID:	1-72-1622891.1
Update Date:	2018-01-01
Keywords:

Solution Type Problem Resolution Sure

Solution 1622891.1 : OBIEE Dashboards On Exalytics Fail With Error:" [nQSError: 16002] Cannot obtain number of columns for the query result... " If Running TimesTen Aggregate Refresh Simultaneously

Applies to:

Exalytics In-Memory Machine X2-4 - Version All Versions and later
Business Intelligence Server Enterprise Edition - Version 11.1.1.7.1 to 11.1.1.7.1 [Release 11g]
Oracle TimesTen In-Memory Database - Version 11.2.2.5.0 and later
Information in this document applies to any platform.

Symptoms

An Exalytics server environment includes TimesTen 11.2.2.5+ and Oracle Business Intelligence Enterprise Edition (OBIEE) 11.1.1.7.1. If the OBIEE Administrator is running TimesTen Aggregate refresh via the NQCMD command, and system users try to access certain OBIEE dashboards and reports at the same time, the following errors are encountered:

Error
View Display Error

Odbc driver returned an error (SQLExecDirectW).
Error Details
Error Codes: OPR4ONWY:U9IM8TAC:OI2DL65P
State: HY000. Code: 10058. [NQODBC] [SQL_STATE: HY000] [nQSError: 10058] A general error has occurred. [nQSError: 43113] Message returned from OBIS. [nQSError: 43119] Query Failed: [nQSError: 16001] ODBC error state: S0002 code: 2206 message: [TimesTen][TimesTen 11.2.2.5.0 ODBC Driver][TimesTen]TT2206: Table TTEXALYTICS.SA_DETAIL00035407 not found -- file "comp.c", lineno 2852, procedure "sbCompCacheTbl()". [nQSError: 16002] Cannot obtain number of columns for the query result. (HY000)
SQL Issued: SET VARIABLE Org_Type='PRIMARY';SELECT s_0, s_1, s_2, s_3, s_4, s_5, s_6, s_7, s_8, s_9, s_10, s_11, s_12, s_13, s_14, s_15, s_16, s_17, s_18, s_19, s_20, s_21, s_22, s_23, s_24, s_25

Cause

This problem is described in Bug 17654039 - OBIEE DASHBOARD/REPORTS FAILING WHILE REFRESHING THE TIMESTEN AGGREGATES. Oracle Development found that it occurs when aggregates are getting deleted using the "delete aggregates" command. If OBIEE requests are run at the same time, the logical SQL may be run against tables that have temporarily dropped from the database (due to aggregate refresh process) and the errors will occur.

Solution

This problem may be prevented by scheduling TT aggregate refresh during idle/or inactive times (i.e. when users will not be running OBIEE requests and dashboards).

If this is not possible, you may apply Patch 17654039. This patch must be applied on top of OBI 11.1.1.7.1 and is available on My Oracle Support (MOS).

NOTE: As with all one-off patches, it is recommended that you first test the patch on a development or test server to ensure it works as expected and does not cause any change in expected behavior.

References

<BUG:17654039> - OBIEE DASHBOARD/REPORTS FAILING WHILE REFRESHING THE TIMESTEN AGGREGATES
<BUG:17654039> - OBIEE DASHBOARD/REPORTS FAILING WHILE REFRESHING THE TIMESTEN AGGREGATES
<NOTE:1611164.1> - Exalytics: OBIEE 11g Dashboard Fails With Errors: "[nQSError: 16002] Cannot obtain number of columns for the query result...TT4053: Assertion Failure"

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