Forum posts to 'Limitations and Known Issues'

"Save as workbook" limitations

Inbal — Mon, 15 Feb 2010 09:31:35 +0000

A new feature in Qure v2.0 - the "save as workbook" option exports most of the analysis information to an excel report.
Please note that this option is only supported in Office 2003 or later.

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Qure V2 multi database analysis limitations

Ami — Tue, 12 Jan 2010 13:52:17 +0000

Starting from version 2.0, Qure enables multi database analysis.

> Trial analysis is limited to a maximum of 2 databases per analysis.
> Full (licensed) analysis is limited to a maximum of 3 databases per analysis.

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SQL Server version and compatibility level support

Ami — Thu, 19 Mar 2009 11:30:59 +0000

Qure supports analyzing databases that use SQL Server 2005/2008 and have a compatibility level of 90 or 100.
If your database was migrated from SQL Server 2000 and its compatibility level was left at its previous setting of 80, you can try and change its compatibility level to 90.
Note that changing the compatibility level may fail, subject to the backward compatibility issues as published by Microsoft in the Books On Line article “SQL Server 2005 Database Engine Backward Compatibility”.

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Database default collation support

Ami — Thu, 19 Mar 2009 11:29:58 +0000

Qure does not support analyzing databases with default case sensitive collations.
For more information about database collations, see the Books On Line article ”Collation Options and International Support”.

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T-SQL Parsing limitations

Ami — Thu, 19 Mar 2009 11:29:12 +0000

The Qure parser does not support parsing and analysis of the following types of queries:

Queries that use quoted identifiers
Qure does not support parsing queries that use quoted identifiers for object names such as “Table1” instead of [Table1].
This is an inherited limitation as Qure cannot know each process’s run time QUOTED_IDENTIFIER setting.

Dynamic queries in server side objects
A less common query writing technique involves dynamically creating the query as a string literal, and then using EXEC or sp_executesql to execute the string containing the query.
If this dynamic construction of the query is done at the application tier, Qure captures the final constructed query from the trace and then parses and analyzes it.
If the dynamic construction of the query is done in server side objects (such as stored procedures, triggers or functions), Qure is not be able to follow its construction or execution, and is therefore unable to analyze it.
The benchmark process however, executes and records batches that call the containing object, either directly or indirectly.

Extended procedures and CLR objects
Qure does not analyze OLE automation (extended procedures) and CLR objects in the database.
All referenced objects in the queries that use OLE or CLR objects are analyzed, except for the expressions or clauses containing references to either the OLE or CLR objects.

XML X-queries
Qure does not parse X-Query expressions and does not analyze any query that contains an X-Query expression.

Column name resolution limitations
The following column aliasing syntaxes are not supported:

> Aliases provided in an alias list.
For example, SELECT * FROM (<Sub query>) AS X (Alias1, Alias2…)

> Aliases in DELETE and UPDATE using the proprietary additional “FROM” SQL Server syntax.

> Aliases derived from sub queries that use set operators such as Union, Except and Intersect.
For example, SELECT Column1 FROM (<Sub query1> UNION <Sub query2>) AS X.

> Queries that contain any of the above syntax constructs are partially analyzed.

ODBC Date and time formats
ODBC specific Date & Time formats are not supported. For example, “{d '1998-02-23'}”

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SQL Server 2008 error logs analysis support

Ami — Thu, 19 Mar 2009 11:26:25 +0000

Collecting and analyzing error log information of SQL Server 2008 is not supported.

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Benchmark limitations

Ami — Thu, 19 Mar 2009 11:25:03 +0000

> Server side cursors and prepare/exec statements are partially supported in benchmark.
These include sp_cursoropen, sp_cursorprepare, sp_cursorprepexec, sp_prepare and sp_prepexec.
Qure extracts the query from the string literal of these commands and treats it as if it were a regular query.
The fetch commands are ignored and the benchmark will show the improvement gained only for the query.

> Schema column modifications may fail to apply in benchmark if any objects, other than indexes or statistics, are dependent upon the column.
You should manually drop any referencing objects in order to modify the column and recreate them after modifying the column properties.

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SQL Server client tools version compatibility

Ami — Thu, 19 Mar 2009 11:24:16 +0000

The version of the installed client tools must be the same or of a higher version than the version of the Profiler or server that generated the trace file.
A trace file generated by Profiler 2008 or a server side trace of SQL Server 2008 cannot be used if Qure is installed on a computer with SQL 2005 client tools.

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Analysis data file 4GB size limit

Ami — Thu, 19 Mar 2009 11:23:02 +0000

Qure uses an internal repository (Analysis data file) for storing all analysis and benchmark information.
The repository has an embedded limit on its size which cannot exceed 4GB.
As a result, the trace analysis process stops analyzing the trace files if the repository reaches a size of 2 GB, in order to leave sufficient space for the benchmark and other data.
This means that only batches captured up to that time are analyzed.
Qure displays an informational message if this size limit is reached.
If your system contains an exceptionally large number of unique batches, the benchmark process may exhaust the available space of the repository.
In this rare case, the benchmark stops and an informational message is displayed.
Benchmark results for batches benchmarked successfully up to that point are available.

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Analysis and benchmark time limits

Ami — Thu, 19 Mar 2009 11:22:09 +0000

Qure uses complex AI algorithms to analyze your database and its activities.
On complex databases with many objects and a large number of unique activities, the analysis and benchmark processes may take considerable time and resources to complete. To avoid the potentially very long duration of these processes (as much as a few days), the following limitation are imposed by Qure:

> The time limit for the trace analysis, which is typically the longest phase of the analysis process, is set to 20 hours.
After 20 hours, the trace analysis is stopped and only batches analyzed up to that point are used to generate recommendations.

> The benchmark uses a database connection with a timeout limit of 600 seconds.
This means that any batch that takes longer than 10 minutes to complete, either before or after the recommendations are applied, will fail the benchmark.

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Opening a report may take a long time

Ami — Thu, 19 Mar 2009 11:20:47 +0000

Depending on the analysis data file size, the number and complexity of the database objects, batches and recommendations, opening a report may take up to a few minutes.
In some cases, especially after the analysis data file is first copied to the local computer, the Windows operating system may indicate that Qure is “not responding”. It is caused by a known issue in SQLCE, click here for more details.
Ignore this warning and wait for Qure to complete loading the report.

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Unhandled exception in recommendations window

Ami — Thu, 19 Mar 2009 11:19:48 +0000

In some cases, selecting a large number of recommendations when the “script preview” pane is active, and attempting to change the status of these recommendations before the script generation completes may cause an unhandled exception message to appear.
Click ’OK’ to close the exception window and Qure should resume normal operation.

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