Virtualization and Databases

In Chris Brown‘s Virtualization and ASE blog post, he brings up the question of whether Sybase’s ASE can be used in a virtual environment (VMWare, Xen, etc) but doesn’t answer it. I’ve been using various databases in virtual environments for several years, here is what I found out:

Running ASE, ASIQ, or SQL Anywhere under virtualization software such as Xen, VMWare, Parallels, etc is very useful under a number of situations:

  1. development of new applications – each developer group can have its own “db server” on the same machine
  2. testing new ebfs/releases with your applications
  3. reproducing problems either in the sybase software or in the application code – a ‘virgin’ instance that can be duplicated at will
  4. trying out new operating systems (moving from Windows to Linux or Windows to Solaris x86?) without investing in new hardware

The main caveat is that the performance stinks – databases typically require high disk i/o, memory i/o and cpu responsiveness. The virtualization software currently available, even with hardware help (newer Intel,AMD chips), are not up to the task of running a *production* database.  In a couple years… possibly.

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Monitoring Databases – what’s wrong with that?

Most database monitoring systems aren’t from the database vendors as you might think, but a hodge-podge of 3rd party vendors that seem to want to charge more than I make in a lifetime for database monitoring software — try finding low cost monitoring software for DB2 on the mainframe.

They typically use standardized, and often deprecated, monitor counters that when used for their product, interfere with any other monitoring products you might use.  For example, if the Operations Department is using Nimbus to monitor the network, VoIP, hosts, tape archival systems, and the database servers to ensure that they are running, what happens when the DBAs want to use DBA Expert? The two products (keep in mind that I chose the products for the example at random) will trip over each other – neither will provide reliable metrics of the databases.

The front ends for the monitoring products always seem to show a fancy GUI full of bright colors, dials, graphs, and the latest and greatest designer kitchen sink. They are very rarely willing to provide any documented API or mechanism for you to obtain the data from their product without a nasty NDA. The premise is that you will use their front end to display and analyze the monitoring metrics.

The database vendors, themselves, are largely to blame. The monitoring APIs that they offer assume that you will only be using a single monitoring system.  For example, in Sybase’s ASE, the new API is to use their MDA tables to obtain performance metrics but the problem comes in when the monitoring software would use multiple methods to obtain additional information that may not be (easily) obtainable from the MDA tables.  sp_sysmon will reset several monitoring counters unless you call it with the ‘noclear’ option.  Unfortunately, the ‘noclear’ is not widely known and rarely used in the monitoring software.  Of course, this is just an example of multiple monitoring APIs from a database vendor.

You know what? I don’t care about the vendors’ fancy front ends. Give me a web service that I can access and use the monitoring metrics in another application, a PDA, etc. A few vendors have tried to offer an API but they are often so damned complicated that you would have had to work at the company to understand the API.  Don’t even get me started on vendors keeping their APIs updated.

Update:  Thanks goes to Peter Dorfman of Sybase to helping clarifying that the MDA tables in ASE ‘clear’ only on a connection basis.  That means if you look at monDeadlocks on connection #1 twice, the first select might show 5 rows and the second 0 rows.  If you ran the select on connection #2 sometime later, you would see the 5 rows plus any other deadlocks that might have occurred since then.  I wasn’t very clear on that as I was (in my head) also including sp_sysmon and other monitoring options that would conflict with the MDA tables.

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Sybase ASE: dbcc dbrepair and writepage/readpage

Does anyone know the syntax for the dbcc dbrepair commands writepage and readpage for Sybase ASE?  These are being used by Whitesands’s ProActive DBA.

The equivalent on Microsoft SQL Server are:

dbcc readpage ({ dbid, 'dbname' }, fileid, pageid, 
    formatstr [, printopt = { 0 | 1} ])
dbcc writepage ({ dbid, 'dbname' }, fileid, pageid,
    offset, length, data)

UPDATE!
I’ve figured out readtext:

dbcc dbrepair(<database name|dbid>, readpage, <page number>)

Continue reading “Sybase ASE: dbcc dbrepair and writepage/readpage”

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Empower for ISV

In case you're looking for reasonably priced Visual Studio .Net
http://www.empowerforisv.com/

You need to have a company web site, and you need to agree to:

Develop one packaged and resalable software application that supports at least one of these Microsoft technologies:

  • Windows Server 2003
  • Windows XP
  • Microsoft SQL Server 2000
  • Microsoft Dynamics, formerly known as Microsoft Business Solutions
  • Microsoft Mobility platform (Microsoft Windows Mobile software for Pocket PCs or Microsoft Windows Mobile software for Smartphones)
Thanks goes to Bruce Armstrong for pointing this out! Cool 
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A good history on Microsoft SQL Server & Sybase relationship

 

There are lots of variations on this myth that I have heard/read over the years, most amusing of which is probably “Microsoft has not had time to mess up the Sybase code it bought yet so SQL Server is still a pretty solid product”

 

Lets start with a history lesson, you can read a much more in depth (and insightful) version of this in the book Inside SQL Server by Microsoft Press (at this time I can only check the 7.0 and 2000 versions) or any of the historical posts/articles by Hal Berenson (former Architect, PUM and GM of SQL Server during 6.5/7.0/2000).

Read more on Euan Garden’s Blog.

 

Euan’s explanation of what happened is pretty close to what I was told by people that were involved in the deal while I was at Sybase.  There are a few differences regarding how the relationship broke down but that appears more of hearsay and point of view issue.  IMHO, I believe that both Microsoft and Sybase were guilty of screwing each other over.  However, that is so far in the past, that it really doesn’t matter.

Interestingly, Sybase still owns the trademark on SQL Server.  Make of that as you will but it is little more than a trivia answer.

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FW: Sybase vs. Oracle: Users speak out

By Elisa Gabbert, Assistant Editor
15 Aug 2006 | SearchOracle.com

A recent column by Mich Talebzedah touting the merits of Sybase on Linux over Oracle as a database management system (DBMS) has our readers riled up.

Anil Mahadev is a DBA and tech writer whose company, based in India, manages Oracle, SQL Server, DB2 and Sybase databases. Having worked with both Oracle and Sybase systems, Mahadev finds that Sybase is "definitely easier to manage and use." He cited seven reasons to opt for Sybase, including programming advantages, startup time and ease of installation. He also concurs with Talebzedah’s claim that switching from Sybase to Oracle is rarely worth the trouble.  Read more….

 

I have to agree with both sides of the discussion.  Sybase’s (and Microsoft’s for that matter) Transact SQL is very limiting for a developer.  Oracle’s PL/SQL is a far more mature SQL dialect.

Compared to other SQL dialects, TSQL appears to be archaic in both functionality and extendability.  Both vendors have made attempts to developer usability with .NET (Microsoft) and Java (Sybase) with varied success.  When calling in an issue involving either a .NET assembly or a java class, Microsoft’s support staff tend to be better trained than Sybase’s support staff, in so much as Microsoft’s support staff are able to determine whom internally they need to contact for help. 

Sybase’s support of Java in the database is limited to a very small number of tech support people.  There isn’t a whole lot of demand for Sybase’s java in the database due to the high cost of this add on and ongoing stability and performance issues with the JVM being run from within ASE itself.

The extendability of the open source DBMSs MySQL and Postgres far exceed their proprietary counterparts (Oracle, MS SQL Server, Sybase ASE).  Not only are there many interpretors that can be used in lieu of SQL, but you can create your own with little trouble.  The commercial companies should take note of this.

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