DB2 v MySql

Collapse
This topic is closed.
X
X
 
  • Time
  • Show
Clear All
new posts
  • Mairhtin O'Feannag

    DB2 v MySql

    Hello,

    I have a client (customer) who asked the question : "Why would I buy and
    use UDB, when MySql is free?"

    I had to say I was stunned. I have no experience with MySql, so I was
    left sort of stammering and sputtering, and managed to pull out something
    I heard a couple of years back - that there was no real transaction
    safety in MySql. In flight transactions could be lost.

    I felt like SUCH a dork.

    I'm bracing for a deluge of flames and/or admonitions, but I'm still
    going to ask:

    What are the deficiencies of MySql that I and my clients should be aware
    of? There are loads of people pushing MySql, and I don't want to get
    into a religious war with ANYONE. I just need a decent answer to the
    question I was asked. :)

    TIA

    Mairhtin
  • Jan M. Nelken

    #2
    Re: DB2 v MySql

    Mairhtin O'Feannag wrote:
    [color=blue]
    > I have a client (customer) who asked the question : "Why would I buy and
    > use UDB, when MySql is free?"[/color]

    If I was asked this question - I would start from here - just to familiarize
    myself with that beast:



    Jan M. Nelken

    Comment

    • Re_endian_miss@yahoo.com

      #3
      Re: DB2 v MySql

      Is there a reason why you're NOT considering MySql? For example, if the
      system is mission-critical and the belief is that DB2 is more
      field-tested/stable and enterprise-feature-rich, and the support from
      IBM exceeds that of third-party MySql support, then this may justify
      Db2. Perhaps the solution you offer leverages some DB2
      knowledge/experience. Again, none of this is a blunt "A is better than
      B because..." argument, but if the customer has any business savvy,
      they may appreciate your honesty, and that not all business decisions
      can be made purely on technical merit.

      Also, this article may be of interest:


      Comment

      • Christopher Browne

        #4
        Re: DB2 v MySql

        "Mairhtin O'Feannag" <irishboyca@roc ketmail.com> writes:[color=blue]
        > What are the deficiencies of MySql that I and my clients should be aware
        > of? There are loads of people pushing MySql, and I don't want to get
        > into a religious war with ANYONE. I just need a decent answer to the
        > question I was asked. :)[/color]

        You might find it worthwhile to look at the following:

        <http://sql-info.de/mysql/gotchas.html>

        It is also rather stupid to claim that "MySQL is free" when their
        price sheets declare otherwise. MySQL(tm) is certainly _not_ free
        when their web site <https://order.mysql.com/> indicates:

        "MySQL Database Server

        The world's most popular open source database. Fast, stable,
        compact.

        Starting at $595.00"
        --
        let name="cbbrowne" and tld="cbbrowne.c om" in String.concat "@" [name;tld];;

        A VAX is virtually a computer, but not quite.

        Comment

        • kenfar

          #5
          Re: DB2 v MySql

          Mairhtin O'Feannag wrote:
          [color=blue]
          > What are the deficiencies of MySql that I and my clients should be[/color]
          aware[color=blue]
          > of?[/color]

          Well, in my opinion this is a product that was at the right place at
          the right time - and surged in popularity along with php, etc a few
          years ago. It can be simple to use, but has such tremendous
          disadvantages that many developers are now leaving it for its open
          source rivals (postgresql & firebird). Anyhow, here's my $0.02.

          1. integrity problems - of various types:
          a. tons of silent errors in which data is truncated, converted,
          etc without an exception passed to the application. Many of these are
          documented widely, including at: //sql-info.de/mysql/gotchas.html
          b. the leadership at this company has stated for years that 99%
          of the developers out there don't need transactions, subselects, views,
          etc. This was misleading from the begining - and they're still rushing
          to quickly add these basics from 20 years ago into their product. In
          the meanwhile, many of these newly-added features are still very beta -
          such as the way that they get transactions through a completely
          separate storage library (innodb). Use of this critical component
          drastically reduces performance, and isn't completely integrated into
          mysql.

          2. performance issues:
          a. it's very much oriented towards read-only transactional
          queries (and it can be very fast at this). However, not many
          applications meet that need except perhaps content management. It has
          a much more difficult time with a balanced workload than most other
          products in this category.
          b. there are almost no reporting/dss features: no partitioning,
          no bitmap indexes, no parallelism, etc. This means that a 2-way
          oracle/db2 server using partitioning/mdc could easily out-perform an
          8-way server running mysql. And these types of queries are becoming
          increasinly common within operational/transaction applications - so
          this isn't just a data warehousing issue.

          3. availability & reliability:
          a. mysql can maintain reasonable availability numbers - but lacks
          a credible clustering offering for higher numbers.
          b. given its silent errors, and penchant for associated data
          corruption problems - it's entirely possible for mysql to stay up and
          continue to serve data - in spite of the data being corrupted.

          4. cost:
          a. the licensing cost for mysql is about the same as any other
          entry-level database. I think the only really inexpensive situation is
          when you need quite a few small open-source databases. Online backups
          are an additional cost,.

          5. portability:
          a. the missing features in mysql (views, etc) often require that
          applications are written differently than if they were to be written
          for a more full-featured database. This limitation results in
          application complexity, database complexity and performance impacts.
          Should the application need to be moved to another database for
          improved performance, it may also require a more significant rewrite
          than if it was built for a different database product.
          b. lack of ansi compliance: mysql ab has shown a considerable
          disregard for ANSI SQL standards (uses '#' instead of '--' for
          comments, etc, etc). MySQL is probably the least compliant RDBMS I've
          seen since the 80s.

          6. Consistency: since there are so many data management jobs that
          mysql can't do - that db2, oracle, etc can - it's not unlikely that a
          shop that uses mysql will also have to use a second database as well.
          As the number of database products grows - so does the labor cost to
          maintain and develop for them. And since the entry-level versions of
          db2, etc are very inexpensive (can be less than MySQL), a savings can
          often be made on the labor side by just going with db2.

          Right now, MySQL does have a few things going for it - primarily
          marketing & momentum. It always gets press when open source databases
          are mentioned, and most folks have heard of it. And it is improving
          rapidly, though I suspect that it's years away from delivering what we
          take for granted from most other products in this category.

          Probably a bigger threat to db2, oracle, and sql server are Postgresql
          & Firebird. Both are free and reasonably featured. There's still a
          lot that DB2 & Oracle offer over these two products, but the sell has
          to be harder if you're talking small departmental servers, embedded
          databases, etc.

          kenfar

          Comment

          • Gert van der Kooij

            #6
            Re: DB2 v MySql

            In article <60brcbplnt.fsf @dba2.int.liber tyrms.com>, Christopher
            Browne (cbbrowne@acm.o rg) says...[color=blue]
            >
            > It is also rather stupid to claim that "MySQL is free" when their
            > price sheets declare otherwise. MySQL(tm) is certainly _not_ free
            > when their web site <https://order.mysql.com/> indicates:
            >
            > "MySQL Database Server
            >
            > The world's most popular open source database. Fast, stable,
            > compact.
            >
            > Starting at $595.00"
            >[/color]

            Weel, it is free as long as you don't have a problem with the GPL
            license.

            Check http://www.mysql.com/company/legal/licensing/faq.html for a
            full description.

            Comment

            • Christopher Browne

              #7
              Re: DB2 v MySql

              Gert van der Kooij <gert@invalid.n l> writes:[color=blue]
              > In article <60brcbplnt.fsf @dba2.int.liber tyrms.com>, Christopher
              > Browne (cbbrowne@acm.o rg) says...[color=green]
              >>
              >> It is also rather stupid to claim that "MySQL is free" when their
              >> price sheets declare otherwise. MySQL(tm) is certainly _not_ free
              >> when their web site <https://order.mysql.com/> indicates:
              >>
              >> "MySQL Database Server
              >>
              >> The world's most popular open source database. Fast, stable,
              >> compact.
              >>
              >> Starting at $595.00"
              >>[/color]
              >
              > Weel, it is free as long as you don't have a problem with the GPL
              > license.
              >
              > Check http://www.mysql.com/company/legal/licensing/faq.html for a
              > full description.[/color]

              There's considerable nonsequitor there.

              That is, what does it mean to "not have a problem with the GPL
              license"? Actually, there are necessarily some problems with the GPL,
              as if there were _no_ problems with it, they would not have felt the
              need to create the "Library GPL" as an alternative for people to use.

              But what MySQL AB _really_ mean is that if you're using it, they
              suggest you consider buying a commercial license if you have any
              concerns about "safety."



              "In their simplest form, the following are general licensing guidelines:

              * If your software is licensed under either the GPL-compatible
              Free Software License as defined by the Free Software Foundation
              or approved by OSI, then use our GPL licensed version.

              * If you distribute a proprietary application in any way, and you
              are not licensing and distributing your source code under GPL,
              you need to purchase a commercial license of MySQL

              If you are unsure, we recommend that you buy our cost effective
              commercial licenses. That is the safest solution. Licensing
              questions can submitted online for our advice, and we encourage you
              to refer to the Free Software Foundation or a lawyer as appropriate."

              I'm not certain what they intend might be considered "unsafe," but
              frankly, it doesn't matter, because their recommendation is that if
              there is any kind of uncertainty, you should be buying licenses.

              There most certainly _is_ a big whack of uncertainty as to what rules
              might apply to the sort of internal departmental application that
              would fit well with MySQL.

              The people I work for have a Bugzilla instance that presently runs
              against a MySQL database; there's no ambiguity there since Bugzilla is
              licensed under a suitable "free software" license, and nobody there is
              making any changes to Bugzilla.

              They used to run RT (a problem tracker) against MySQL; they helped
              fund the port of RT/3 to PostgreSQL because of the uncertainties
              surrounding cases where there would be a need to write custom reports
              to do additional analysis. There is most definitely some uncertainty
              as to the licensing of those reports, and the implications on how
              licensing requirements would fall out of that.

              I don't know if MySQL AB would require buying a license under that
              sort of circumstance; what I do know is that:

              "If you are unsure, we recommend that you buy our cost effective
              commercial licenses. That is the safest solution."
              --
              let name="cbbrowne" and tld="cbbrowne.c om" in String.concat "@" [name;tld];;

              A VAX is virtually a computer, but not quite.

              Comment

              • Heikki Tuuri

                #8
                Re: DB2 v MySql

                Kenfar,

                "kenfar" <kenfar42@yahoo .com> kirjoitti
                viestissä:11044 48787.555388.49 250@c13g2000cwb .googlegroups.c om...[color=blue]
                > Mairhtin O'Feannag wrote:
                >[color=green]
                >> What are the deficiencies of MySql that I and my clients should be[/color]
                > aware[color=green]
                >> of?[/color]
                >[/color]
                ....[color=blue]
                > the meanwhile, many of these newly-added features are still very beta -
                > such as the way that they get transactions through a completely
                > separate storage library (innodb). Use of this critical component
                > drastically reduces performance, and isn't completely integrated into
                > mysql.[/color]

                MySQL/InnoDB-3.23 was declared stable in 2002. Can you specify some reason
                why you claim MySQL/InnoDB is 'still very beta'?

                InnoDB is even faster than the default table type of MySQL, MyISAM, in many
                simple benchmarks. Can you clarify why you claim InnoDB to 'drastically
                reduce performance'?
                [color=blue]
                > 2. performance issues:
                > a. it's very much oriented towards read-only transactional
                > queries (and it can be very fast at this). However, not many
                > applications meet that need except perhaps content management. It has
                > a much more difficult time with a balanced workload than most other
                > products in this category.[/color]

                MySQL/InnoDB has an architecture rather close to Oracle and PostgreSQL.
                MySQL/InnoDB is oriented towards a mixed workload of reads and writes. On
                the other hand, DB2 lacks the consistent non-locking read capability of
                Oracle, InnoDB, and PostgreSQL. In that respect DB2 is less suitable for a
                mixed workload of reads and writes than those three databases.



                ....[color=blue]
                > 3. availability & reliability:
                > a. mysql can maintain reasonable availability numbers - but lacks
                > a credible clustering offering for higher numbers.[/color]

                Thousands of people use MySQL's replication feature for high availability
                and greater performance of read-heavy workloads.

                By the way, does somebody at this news group know how successful DB2's
                clustering options are commercially? I know that Oracle RAC has been
                moderately successful, but have not heard anything about DB2 offerings.
                ....[color=blue]
                > kenfar[/color]

                Best regards,

                Heikki Tuuri
                Innobase Oy
                Foreign keys, transactions, and row level locking for MySQL
                InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM
                tables



                Comment

                • Data Goob

                  #9
                  Re: DB2 v MySql

                  Heikki Tuuri wrote:[color=blue]
                  > Kenfar,
                  >
                  > "kenfar" <kenfar42@yahoo .com> kirjoitti
                  > viestissä:11044 48787.555388.49 250@c13g2000cwb .googlegroups.c om...
                  >[color=green]
                  >>Mairhtin O'Feannag wrote:
                  >>
                  >>[color=darkred]
                  >>>What are the deficiencies of MySql that I and my clients should be[/color]
                  >>
                  >>aware
                  >>[color=darkred]
                  >>>of?[/color]
                  >>[/color]
                  > ...[/color]



                  MySQL disk management of "tablespace s" is practically non-existent, which is one
                  of my show-stoppers. Most of the deficiencies in the product can be overcome
                  by programming, but data management is very primitive. You must be willing
                  to live with almost no control over where and how you distribute data. This
                  is probably the single biggest area that needs to be improved upon. Yes, you
                  can have shared-nothing databases with the NDB database type, but this is so
                  primitive as to beg the question as to why you would use it rather than a more
                  polished product elsewhere, i.e. DB2. If cost is the factor blah blah blah.
                  These features are interesting and certainly worth investigating but as has
                  already been said, barely out of beta. I do think DB2 could be priced a bit
                  more competitively, but that begs the question of just who IBM are positioning
                  themselves with, and is MySQL in their space.

                  Download the product and see for yourself. But also consider that it may be
                  quite useful to use MySQL along with DB2, rather than an "either-or" mindset.

                  MySQL is great for prototyping applications because it's so easy to get
                  set up, and it makes perfect sense for widely distributed applications like
                  web sites. You can take the speed advantages for many components of
                  your web site with MySQL, and pull in parts of your DB2 database only when
                  you need to thus taking a lot of load off your "expensive" DB2 database. It
                  might be more instructive to have a "MySQL and DB2" approach rather than
                  either-or--taking note that MySQL has its place but as of today does not
                  have the maturity and features of DB2 or Oracle ( or even Sybase or Informix ).

                  -DG-

                  [color=blue]
                  >[color=green]
                  >>the meanwhile, many of these newly-added features are still very beta -
                  >>such as the way that they get transactions through a completely
                  >>separate storage library (innodb). Use of this critical component
                  >>drastically reduces performance, and isn't completely integrated into
                  >>mysql.[/color]
                  >
                  >
                  > MySQL/InnoDB-3.23 was declared stable in 2002. Can you specify some reason
                  > why you claim MySQL/InnoDB is 'still very beta'?
                  >
                  > InnoDB is even faster than the default table type of MySQL, MyISAM, in many
                  > simple benchmarks. Can you clarify why you claim InnoDB to 'drastically
                  > reduce performance'?
                  >
                  >[color=green]
                  >>2. performance issues:
                  >>a. it's very much oriented towards read-only transactional
                  >>queries (and it can be very fast at this). However, not many
                  >>application s meet that need except perhaps content management. It has
                  >>a much more difficult time with a balanced workload than most other
                  >>products in this category.[/color]
                  >
                  >
                  > MySQL/InnoDB has an architecture rather close to Oracle and PostgreSQL.
                  > MySQL/InnoDB is oriented towards a mixed workload of reads and writes. On
                  > the other hand, DB2 lacks the consistent non-locking read capability of
                  > Oracle, InnoDB, and PostgreSQL. In that respect DB2 is less suitable for a
                  > mixed workload of reads and writes than those three databases.
                  >
                  > http://dev.mysql.com/doc/mysql/en/In...ion_model.html
                  >
                  > ...
                  >[color=green]
                  >>3. availability & reliability:
                  >>a. mysql can maintain reasonable availability numbers - but lacks
                  >>a credible clustering offering for higher numbers.[/color]
                  >
                  >
                  > Thousands of people use MySQL's replication feature for high availability
                  > and greater performance of read-heavy workloads.
                  >
                  > By the way, does somebody at this news group know how successful DB2's
                  > clustering options are commercially? I know that Oracle RAC has been
                  > moderately successful, but have not heard anything about DB2 offerings.
                  > ...
                  >[color=green]
                  >>kenfar[/color]
                  >
                  >
                  > Best regards,
                  >
                  > Heikki Tuuri
                  > Innobase Oy
                  > Foreign keys, transactions, and row level locking for MySQL
                  > InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM
                  > tables
                  > http://www.innodb.com/order.php
                  >
                  >[/color]

                  Comment

                  • Heikki Tuuri

                    #10
                    Re: DB2 v MySql

                    DG,

                    "Data Goob" <datagoob@hotma il.com> kirjoitti
                    viestissä:u7TBd .8$8l5.7@fe66.u senetserver.com ...[color=blue]
                    > Heikki Tuuri wrote:[color=green]
                    >> Kenfar,
                    >>
                    >> "kenfar" <kenfar42@yahoo .com> kirjoitti
                    >> viestissä:11044 48787.555388.49 250@c13g2000cwb .googlegroups.c om...
                    >>[color=darkred]
                    >>>Mairhtin O'Feannag wrote:
                    >>>
                    >>>
                    >>>>What are the deficiencies of MySql that I and my clients should be
                    >>>
                    >>>aware
                    >>>
                    >>>>of?
                    >>>[/color]
                    >> ...[/color]
                    >
                    >
                    >
                    > MySQL disk management of "tablespace s" is practically non-existent, which
                    > is one
                    > of my show-stoppers. Most of the deficiencies in the product can be
                    > overcome
                    > by programming, but data management is very primitive. You must be
                    > willing
                    > to live with almost no control over where and how you distribute data.
                    > This[/color]

                    there are the following mechanisms to place InnoDB data on the chosen disk
                    drives:

                    1) create several ibdata files, and distribute them on the drives; this is
                    simple kind of 'striping';

                    2) use per-table tablespaces in 4.1, and symlink database directories (or
                    individual tables) where you want. That 4.1 feature is still in beta,
                    though.

                    The reason why we have not implemented the complete Oracle-like tablespace
                    support is that no one has come up with a reason why we should do it. If you
                    want disk striping to balance the load between individual physical disk
                    drives, you can use OS or hardware solutions. Or you can use the techniques
                    1 and 2 described above.

                    Partitioned tables are currently in development for MySQL, and they may
                    appear in some 5.x version.
                    ....[color=blue]
                    > -DG-[/color]

                    Best regards,

                    Heikki Tuuri
                    Innobase Oy
                    Foreign keys, transactions, and row level locking for MySQL



                    Comment

                    • kenfar

                      #11
                      Re: DB2 v MySql

                      Heikki Tuuri wrote:
                      [color=blue]
                      > MySQL/InnoDB-3.23 was declared stable in 2002. Can you specify some
                      > reason why you claim MySQL/InnoDB is 'still very beta'?[/color]


                      I said some of the new features are still beta. That's not really fair
                      - mysql ab calls them stable. It's just my opinion that they're only
                      halfway there with much of this functionality. Like:

                      1. RI & Transactions are now supported. However...

                      When creating tables in mysql if there's a problem with innodb mysql
                      will simply create the tables in myisam instead - and you will have
                      silently lost all transaction support for that table. Nice surprises
                      can result from this.

                      Exception handling - a weak spot in the mysql product is even worse
                      with subqueries, from the documentation: "Usually, failure of a
                      subquery causes the entire statement to fail." Ah, neat.

                      Primary Key definitions - are implicit if not provided, causing mysql
                      to confuse them with unique indexes, and requiring fk syntax to specify
                      the pk column.

                      Alter Table - is apparently half-implemented for innodb - since just
                      adding an index causes a table to be rebuilt. Note that this alter can
                      easily fail if you don't have enough storage to double the size of the
                      original table.

                      Identity columns are partially working with innodb - there's no way to
                      manually reset a value. Recommended solution is to insert a dummy row
                      when this is needed.

                      Innodb & replication is still missing some basic features. From the
                      doc: "The LOAD TABLE FROM MASTER statement for setting up replication
                      slave servers does not yet work for InnoDB tables. A workaround is to
                      alter the table to MyISAM on the master, do then the load, and after
                      that alter the master table back to InnoDB."

                      2. Subqueries are now supported. However...

                      Performance is pretty uneven - understandable since they've now got to
                      work on
                      the optimizer. MySQL doesn't have much to say about that except
                      "Developmen t is ongoing, so no optimization tip is reliable for the
                      long term". In other words - the application developer will likely
                      have to experiment with several versions of their query, then expect to
                      do it all over again when the performance nose-dives after a mysql
                      upgrade 1-2 years from now. Nothing really wrong with this - users of
                      most other databases had to do the same thing. Like around 1985-1989
                      or so...

                      etc, etc.


                      [color=blue]
                      > InnoDB is even faster than the default table type of MySQL, MyISAM,[/color]
                      in many[color=blue]
                      > simple benchmarks.[/color]

                      Right - since all MyISAM writes involve table locks, it doesn't take
                      much writing to completely kill performance on that table type. Prior
                      to adding innodb, mysql probably had the worst write peformance (or
                      mixed-load) of any database product I can think of except for MS
                      Access. And even that's debatable.

                      So, Innodb brings acceptable write performance to mysql. That's cool.
                      But it doesn't improve on its read-performance. In fact, most
                      experiences I've seen seem to indicate that it's about 1/10th the speed
                      of the isam solution. Which isn't necessarily a killer - since you can
                      mix table types. But if you need performance from a table you're
                      writing a lot to, it looks like you're out of luck with mysql for now.

                      Typical comment:
                      "MyISAM will be faster than InnoDb for reading. In my tests, MyISAM was
                      about 10x faster than an untuned InnoDb installation for simple Select
                      statements. InnoDb is capable of faster speeds but requires a lot of
                      tuning to get the peak performance from it. InnoDb is great for updates
                      but for reading I prefer MyISAM hands down." -

                      [color=blue]
                      >From the documentation: "and another site handles an average load of[/color]
                      800 inserts/updates per second in InnoDB." I think that's about where
                      DB2 & Oracle were around 1995...

                      Then there's the odd way that mysql gathers stats for indexes: it
                      performs ten random samples of the index to gather stats. This is
                      acknowledged as often inaccurate with MySQL recommending the hint
                      "force index X" as a solution. That's great - nothing like having to
                      include index names in your application queries!

                      There may be some ways that innodb can leverage storage creatively for
                      additional speed - but since it already consumes 50-300% more space
                      than innodb, perhaps that isn't an economical option at this time.
                      [color=blue]
                      > MySQL/InnoDB has an architecture rather close to Oracle and
                      > PostgreSQL. MySQL/InnoDB is oriented towards a mixed workload
                      > of reads and writes. On the >other hand, DB2 lacks the
                      > consistent non-locking read capability of Oracle, InnoDB, and
                      > PostgreSQL. In that respect DB2 is less suitable for a mixed
                      > workload of reads and writes than those three databases.[/color]

                      There are no published benchmarks of mysql on www.tpc.org, but if
                      mysql's claim to fame is 800 inserts / second then it's got a long way
                      to go before it can handle the mixed workload of db2.

                      Not really sure if MySQL's clustering or MAXDB enter the picture here.
                      MAXDB is really just adabase - a heap of pre-relational code. The
                      clustering solution that MySQL purchased sounds interesting - but it's
                      limited to data stored in memory. The lack of persistence sounds
                      unappealing for transactional data, and the cost of memory rules out
                      most large read-only systems.

                      [color=blue]
                      >Thousands of people use MySQL's replication feature for high[/color]
                      availability[color=blue]
                      >and greater performance of read-heavy workloads.[/color]


                      Regarding replication for high availability - it's only HA for the
                      read-only data, since mysql only supports a single master.

                      Regarding replication for performance - this strategic is especially
                      problematic for several reasons:

                      - load-balancing across replicated servers can result in RI-like
                      inconsistencies in which your data appears & disappears, depending on
                      which server you're hitting.

                      - replication won't perform transformation, and you typically get *far*
                      better performance improvements from remodeling your oltp data than
                      from rehosting it. A simple ETL solution would often be preferable
                      here.

                      - mysql's lack of partitioning & parallelism is hardly compensated for
                      via replicated servers: since each server has 100% of the data, queries
                      aren't split up across servers - and the single performance strategy is
                      still "force an index". All that it achieves is to reduce the load by
                      distributing the queries across additional hardware. In an adhoc
                      environment with large data and few queries,mysql would get tanked.
                      And replication would offer no help whatsoever.

                      [color=blue]
                      >By the way, does somebody at this news group know how successful DB2's[/color]
                      [color=blue]
                      >clustering options are commercially? I know that Oracle RAC has been[/color]
                      [color=blue]
                      >moderately successful, but have not heard anything about DB2[/color]
                      offerings.

                      DB2 doesn't map directly to RAC - performance is achived through a
                      mature shared-nothing partitioning feature. This scales well to many
                      terrabytes and hundreds of nodes. Failover is usually provided via
                      HACMP, etc.

                      Although some folks slam MySQL for using both innodb & myisam, I think
                      it's fine. There's certainly an occasional need for non-logged DML.
                      And a number of the pieces in the overall mysql solution look good -
                      innodb & clustering for instance. But the code that glues them all
                      together into a solution that provides integrity and reliability is
                      completely lacking. If they can clean that up then they'll have a nice
                      product. And maybe a reason to look at mysql rather than a more robust
                      alternative such as postgresql, firebird, db2, oracle, etc.

                      kenfar

                      Comment

                      • ak_tiredofspam@yahoo.com

                        #12
                        Re: DB2 v MySql

                        >> Exception handling - a weak spot in the mysql product is even worse
                        with subqueries, from the documentation: "Usually, failure of a
                        subquery causes the entire statement to fail." Ah, neat
                        ....<<

                        what do you mean by this?
                        Do you mean it should ALWAYS cause an exception?

                        Comment

                        • DA Morgan

                          #13
                          Re: DB2 v MySql

                          ak_tiredofspam@ yahoo.com wrote:
                          [color=blue][color=green][color=darkred]
                          >>>Exception handling - a weak spot in the mysql product is even worse[/color][/color]
                          >
                          > with subqueries, from the documentation: "Usually, failure of a
                          > subquery causes the entire statement to fail." Ah, neat
                          > ...<<
                          >
                          > what do you mean by this?
                          > Do you mean it should ALWAYS cause an exception?[/color]

                          I think ALWAYS would be a reasonable expectation.
                          --
                          Daniel A. Morgan
                          University of Washington
                          damorgan@x.wash ington.edu
                          (replace 'x' with 'u' to respond)

                          Comment

                          • Serge Rielau

                            #14
                            Re: DB2 v MySql

                            I'm by no means an expert in MySQL, but from the little I have read it
                            seems like following any sort of standard isn't its strength.
                            Not looking ahead, standardize and try to get it right at the first shot
                            means either an excess of "compatibil ity switches", application breakage
                            on upgrade or worse that the product will run itself into the
                            technological ditch within a couple of releases.

                            Just my two cents.

                            Cheers
                            Serge

                            Comment

                            • ak_tiredofspam@yahoo.com

                              #15
                              Re: DB2 v MySql

                              >> I think ALWAYS would be a reasonable expectation
                              ....<<

                              Of course, I'm not an expert on MySQL, but one doesn't have to eat the
                              whole egg...
                              If MySQL ever gets out of diapers, I'll be the first to agree with you.
                              Right now this "feature" seems to be quite consistent with the rest of
                              the product.

                              Comment

                              Working...