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Merge work:/my/mysql into tik.mysql.fi:/home/my/mysql

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monty@tik.mysql.fi 2001-06-11 15:07:42 +03:00
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1
.bzrignore
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@ -284,3 +284,4 @@ support-files/mysql.spec
tags
tmp/*
sql-bench/gif/*
sql-bench/graph-compare-results

3
BitKeeper/etc/logging_ok
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@ -1,4 +1,5 @@
heikki@donna.mysql.fi
jani@janikt.pp.saunalahti.fi
paul@teton.kitebird.com
monty@tik.mysql.fi
mwagner@evoq.mwagner.org
paul@teton.kitebird.com

594
Docs/manual.texi
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@ -686,7 +686,7 @@ System/Compile Time and Startup Parameter Tuning
* Compile and link options:: How compiling and linking affects the speed of MySQL
* Disk issues:: Disk issues
* Symbolic links::
* Symbolic links:: Using Symbolic Links
* Server parameters:: Tuning server parameters
* Table cache:: How MySQL opens and closes tables
* Creating many tables:: Drawbacks of creating large numbers of tables in the same database
@ -952,6 +952,17 @@ How MySQL Compares to @code{mSQL}
* Protocol differences:: How @code{mSQL} and @strong{MySQL} client/server communications protocols differ
* Syntax differences:: How @code{mSQL} 2.0 SQL syntax differs from @strong{MySQL}
How MySQL Compares to PostgreSQL
* MySQL-PostgreSQL goals::
* MySQL-PostgreSQL features::
* MySQL-PostgreSQL benchmarks::
MySQL and PostgreSQL development goals
* MySQL-PostgreSQL features::
* MySQL-PostgreSQL benchmarks::
MySQL Internals
* MySQL threads:: MySQL threads
@ -9000,7 +9011,7 @@ named pipe connections. You should use either @code{mysqld-nt} or
@code{mysqld-max-nt}.)
If @code{mysqld} doesn't start, please check whether or not the
@file{\mysql\mysql.err} file contains any reason for this. You can also
@file{\mysql\data\mysql.err} file contains any reason for this. You can also
try to start the server with @code{mysqld --standalone}; In this case, you may
get some useful information on the screen that may help solve the problem.
@ -9174,14 +9185,12 @@ server, you can do so using this command:
C:\> mysqladmin --user=root --password=your_password shutdown
@end example
If you are using the old shareware version of @strong{MySQL} Version 3.21
under Windows, the above command will fail with an error: @code{parse error
near 'SET OPTION password'}. This is because the old shareware version,
which is based on @strong{MySQL} Version 3.21, doesn't have the
@code{SET PASSWORD} command. The fix is in this case to upgrade to
the Version 3.22 shareware.
If you are using the old shareware version of @strong{MySQL} Version
3.21 under Windows, the above command will fail with an error:
@code{parse error near 'SET OPTION password'}. The fix is in to upgrade
to the current @strong{MySQL} version, which is freely available.
With the newer @strong{MySQL} versions you can easily add new users
With the current @strong{MySQL} versions you can easily add new users
and change privileges with @code{GRANT} and @code{REVOKE} commands.
@xref{GRANT}.
@ -9250,7 +9259,7 @@ Note that the symbolic link will be used only if the directory
For example, if the @strong{MySQL} data directory is @file{C:\mysql\data}
and you want to have database @code{foo} located at @file{D:\data\foo}, you
should create the file @file{C:\mysql\data\foo.sym} that contains the
text @code{D:\data\foo}. After that, all tables created in the database
text @code{D:\data\foo\}. After that, all tables created in the database
@code{foo} will be created in @file{D:\data\foo}.
Note that because of the speed penalty you get when opening every table,
@ -10066,7 +10075,7 @@ correctly, check the log file to see if you can find out why. Log files
are located in the data directory (typically
@file{/usr/local/mysql/data} for a binary distribution,
@file{/usr/local/var} for a source distribution,
@file{\mysql\mysql.err} on Windows.) Look in the data directory for
@file{\mysql\data\mysql.err} on Windows.) Look in the data directory for
files with names of the form @file{host_name.err} and
@file{host_name.log} where @code{host_name} is the name of your server
host. Then check the last few lines of these files:
@ -10611,7 +10620,7 @@ interactive-timeout
@tindex .my.cnf file
If you have a source distribution, you will find sample configuration
files named @file{my-xxxx.cnf} in the @file{support-files} directory.
If you have a binary distribution, look in the @file{DIR/share/mysql}
If you have a binary distribution, look in the @file{DIR/support-files}
directory, where @code{DIR} is the pathname to the @strong{MySQL}
installation directory (typically @file{/usr/local/mysql}). Currently
there are sample configuration files for small, medium, large, and very
@ -19563,6 +19572,11 @@ sequence number by executing @code{SET INSERT_ID=#} before
@code{ALTER TABLE} or using the @code{AUTO_INCREMENT = #} table option.
@xref{SET OPTION}.
With MyISAM tables, if you don't change the @code{AUTO_INCREMENT}
column, the sequence number will not be affected. If you drop an
@code{AUTO_INCREMENT} column and then add another @code{AUTO_INCREMENT}
column, the numbers will start from 1 again.
@xref{ALTER TABLE problems}.
@findex RENAME TABLE
@ -39430,7 +39444,7 @@ switch to a new log) by executing @code{FLUSH LOGS}. @xref{FLUSH}.
@code{mysqld} writes all errors to the stderr, which the
@code{safe_mysqld} script redirects to a file called
@code{'hostname'.err}. (On Windows, @code{mysqld} writes this directly
to @file{mysql.err}).
to @file{\mysql\data\mysql.err}).
This contains information indicating when @code{mysqld} was started and
stopped and also any critical errors found when running. If @code{mysqld}
@ -43585,53 +43599,516 @@ users.
@item
@end table
@cindex PostgreSQL, comparison
@cindex PostgreSQL/MySQL, overview
@node Compare PostgreSQL, , Compare mSQL, Comparisons
@section How MySQL Compares to PostgreSQL
When reading the following, please note that both products are
continually evolving. We at @strong{MySQL AB} and the PostgreSQL
developers are both working on making our respective database as good as
possible, so we are both a serious choice to any commercial database.
The following comparison is made by us at MySQL AB. We have tried to be
as accurate and fair as possible, but because we don't have a full
knowledge of all PostgreSQL features while we know MySQL througly, we
may have got some things wrong. We will however correct these when they
come to our attention.
We would first like to note that @code{PostgreSQL} and @strong{MySQL}
are both widely used products, but their design goals are completely
different. This means that for some applications @strong{MySQL} is more
suitable and for others @code{PostgreSQL} is more suitable. When
choosing which database to use, you should first check if the database's
feature set is good enough to satisfy your application. If you need
speed, @strong{MySQL} is probably your best choice. If you need some
of the extra features that @code{PostgreSQL} can offer, you should use
are both widely used products, but with different design goals, even if
we are both striving to be ANSI SQL compatible. This means that for
some applications @strong{MySQL} is more suitable and for others
@code{PostgreSQL} is more suitable. When choosing which database to
use, you should first check if the database's feature set satisfies your
application. If you need speed, @strong{MySQL} is probably your best
choice. If you need some of the extra features that only @code{PostgreSQL}
can offer, you should use @code{PostgreSQL}.
@cindex PostgreSQL/MySQL, goals
@menu
* MySQL-PostgreSQL goals:: MySQL and PostgreSQL development goals
* MySQL-PostgreSQL features:: Featurevise Comparison of MySQL and PostgreSQL
* MySQL-PostgreSQL benchmarks:: Benchmarking MySQL and PostgreSQL
@end menu
@node MySQL-PostgreSQL goals, MySQL-PostgreSQL features, Compare PostgreSQL, Compare PostgreSQL
@subsection MySQL and PostgreSQL development goals
When adding things to MySQL we take pride to do an optimal, definite
solution. The code should be so good that we shouldn't have any need to
change it in the foreseeable future. We also do not like to sacrifice
speed for features but instead will do our utmost to find a solution
that will give maximal throughput. This means that development will take
a little longer, but the end result will be well worth this. This kind
of development is only possible because all server code are checked by
one of a few (currently two) persons before it's included in the
@strong{MySQL} server.
We at MySQL AB believe in frequent releases to be able to push out new
features quickly to our users. Because of this we do a new small release
about every 3 weeks, which a major branch every year. All releases are
throughly tested with our testing tools on a lot of different platforms.
PostgreSQL is based on a kernel with lots of contributors. In this setup
it makes sense to prioritize adding a lot of new features, instead of
implementing them optimally, because one can always optimize things
later if there arises a need for this.
Another big difference between @strong{MySQL} and PostgreSQL is that
nearly all of the code in the MySQL server are coded by developers that
are employed by MySQL AB and are still working on the server code. The
exceptions are the transaction engines and the regexp library.
This is in sharp contrast to the PostgreSQL code where the majority of
the code is coded by a big group of people with different backgrounds.
It was only recently that the PostgreSQL developers announced that they
current developer group had finally had time to take a look at all
the code in the current PostgreSQL release.
Both of the above development methods has it's own merits and drawbacks.
We here at @strong{MySQL AB} think of course that our model is better
because our model gives better code consistence, more optimal and
reusable code and, in our opinion, fewer bugs. Because we are the
authors of the @strong{MySQL} server code we are better able to
coordinate new features and releases.
@cindex PostgreSQL/MySQL, features
@node MySQL-PostgreSQL features, MySQL-PostgreSQL benchmarks, MySQL-PostgreSQL goals, Compare PostgreSQL
@subsection Featurevise Comparison of MySQL and PostgreSQL
On the @uref{http://www.mysql.com/information/crash-me.php, crash-me}
page you can find a list of those database constructs and limits that
one can detect automatically with a program. Note however that a lot of
the numerical limits may be changed with startup options for respective
database. The above web page is however extremely useful when you want to
ensure that your applications works with many different databases or
when you want to convert your application from one datbase to another.
@strong{MySQL} offers the following advantages over PostgreSQL:
@itemize @bullet
@item
@code{MySQL} is generally much faster than PostgreSQL.
@xref{MySQL-PostgreSQL benchmarks}.
@item
Because @strong{MySQL} has a much larger user base than PostgreSQL the
code is more tested and has historically been more stable than
PostgreSQL. @strong{MySQL} is the much more used in production
environments than PostgreSQL, mostly thanks to that @strong{MySQL AB},
former TCX DataKonsult AB, has provided top quality commercial support
for @strong{MySQL} from the day it was released, whereas until recently
PostgreSQL was unsupported.
@item
@strong{MySQL} works on more platforms than PostgreSQL. @xref{Which OS}.
@item
@strong{MySQL} works better on Windows; @strong{MySQL} is running as a
native windows application (a service on NT/Win2000/WinXP), while
PostgreSQL is run under the cygwin emulation. We have heard that
PostgreSQL is not yet that stable on windows but we haven't been able to
verify this ourselves.
@item
@strong{MySQL} has more API to other languages and is supported by more
programs than PostgreSQL. @xref{Contrib}.
@item
@strong{MySQL} works on 24/7 heavy duty systems. In most circumstances
you never have to run any cleanups on @code{MySQL}. PostgreSQL doesn't
yet support 24/7 systems because you have have to run @code{vacuum()}
once in a while to reclaim space from @code{UPDATE} and @code{DELETE}
commands and to perform statistics analyzes that are critical to get
good performance with PostgreSQL. On a busy system with lots of changes
vacuum must be run very frequently, in the worst cases even many times a
day. During the @code{vacuum()} run, which may take hours if the
database is big, the database is from a production standpoint
practically dead. The PostgreSQL team has fixing this on their TODO,
but we assume that this is not an easy thing to fix permanently.
@item
A working, tested replication feature used by sites like
@uref{http://finance.yahoo.com, Yahoo finance},
@uref{http://www.mobile.de/,mobile.de} and
@uref{http://www.slashdot.org,Slashdot}.
@item
Included in the @strong{MySQL} distribution is included two different
testing suits (@file{mysql-test-run} and
@uref{http://www.mysql.com/information/crash-me.php,crash-me}) and a
benchmark suite. The test system is actively updated with code to test
each new feature and almost all repeatable bugs that comes to our
attention. We test @strong{MySQL} with these on a lot of platforms
before every release. These tests are more sofisticated than anything
have seen from PostgreSQL and ensures that the @strong{MySQL} code keeps
at a high standard.
@item
There are far moore books in print on @strong{MySQL} than on PostgreSQL.
O'Reilly, Sams, Que, and New Riders are all major publishers with books
about MySQL. All @strong{MySQL} features is also documented in the
@strong{MySQL} on-line manual because when a feature is implemented, the
@strong{MySQL} developers are required to document it before it's
included in the source.
@item
@strong{MySQL} has supports more of the standard ODBC functions than
@code{PostgreSQL}.
@item
@strong{MySQL} has a much more sophisticated @code{ALTER TABLE}.
@item
@strong{MySQL} has support for tables without transactions for
applications that need all speed they can get. The tables may be memory
based,@code{HEAP} tables or disk based @code{MyISAM}. @xref{Table types}.
@item
@strong{MySQL} has support for 3 different table handles that support
transactions (@code{BDB}, @code{InnoDB} and @code{Gemini}. Because
every transaction engine performs differently under different
conditions, this gives the application writer more options to find an
optimal solution for his/her setup. @xref{Table types}.
@item
@code{MERGE} tables gives you a unique way to instantly make a view over
a set of identical tables and use these as one. This is perfectly for
systems where you have log files that you order for example by month.
@xref{MERGE}.
@item
The option to compress read-only tables, but still have direct access to
the rows in the table, gives you better performance by minimizing disk
reads. This is very useful when you are archiving
things.@xref{myisampack}.
@item
@strong{MySQL} has internal support for text search. @xref{Fulltext Search}.
@item
You can access many databases from the same connection (depending of course
on your privileges).
@item
@strong{MySQL} is coded from the start with multi-threading while
PostgreSQL uses processes. Because context switching and access to
common storage areas is much faster between threads, than are separate
processes, this gives @strong{MySQL} a big speed advantage in multi-user
applications and also makes it easier for @strong{MySQL} to take full
advantage of symmetric multiprocessor systems (SMP).
@item
@strong{MySQL} has a much more sophisticated privilege system than
PostgreSQL. While PostgreSQL only supports @code{INSERT},
@code{SELECT}, @code{update/delete} grants per user on a database or a
table @strong{MySQL} allows you to define a full set of different
privileges on database, table and columns level. @strong{MySQL} also allows
you to specify the privilege on host+user combinations. @xref{GRANT}.
@item
@strong{MySQL} supports a compressed server/client protocol which
improves performance over slow links.
@item
@strong{MySQL} employs the table handler concept and is the only
relational database we know of built around this concept. This allows
different low level table types to be swapped into the SQL engine, each
table type optimized for a different performance characteristics.
@item
All @code{MySQL} table types (except @strong{InnoDB}) are implemented as
files (ie: one table per file), which makes it really easy to backup,
move, delete and even symlink databases and tables when the server is
down.
@item
Tools to repair and optimize @strong{MyISAM} tables (the most common
@strong{MySQL} table type). A repair tool is only needed when a
physical corruption of a data file happens, usually from a hardware
failure. It allows a majority of the data to be recovered.
@item
Upgrading @strong{MySQL} is painless. When you upgrading @strong{MySQL},
you don't need to dump/restore your data, as you have to do with most
PostgreSQL upgrades.
@end itemize
@code{PostgreSQL} has some more advanced features like user-defined
types, triggers, rules, and some transaction support (currently it
has about the same semantics as @strong{MySQL}'s transactions in that the
transaction is not 100% atomic). However, PostgreSQL lacks many of the
standard types and functions from ANSI SQL and ODBC. See the @code{crash-me}
Web page (@uref{http://www.mysql.com/information/crash-me.php}) for a complete
list of limits and which types and functions are supported or unsupported.
Drawbacks with @strong{MySQL} compared to PostgreSQL:
Normally, @code{PostgreSQL} is a magnitude slower than @strong{MySQL}.
@xref{Benchmarks}. This is due largely to the fact that they have only
transaction-safe tables and that their transactions system is not as
sophisticated as Berkeley DB's. In @strong{MySQL} you can decide per
table if you want the table to be fast or take the speed penalty of
making it transaction-safe.
@itemize @bullet
@item
The transaction support in @strong{MySQL} is not yet as well tested as
PostgreSQL's system.
@item
Because @strong{MySQL} uses threads, which are still a moving target on
many OS, one must either use binaries from
@uref{http://www.mysql.com/downloads} or carefully follow our
instructions on
@uref{http://www.mysql.com/doc/I/n/Installing_source.html} to get an
optimal binary that works in all cases.
@item
Table locking, as used by the non-transactional @code{MyISAM} tables, is
in many cases faster than page locks, row locks or versioning. The
drawback however is that if one doesn't take into account how table
locks works, a single long-running query can block a table for updates
for a long time. This can usable be avoided when designing the
application. If not, one can always switch the trouble table to use one
of the transactional table types. @xref{Table locking}.
@item
With UDF (user defined functions) one can extend @strong{MySQL} with
both normal SQL functions and aggregates, but this is not as easy or as
flexible as in PostgreSQL. @xref{Adding functions}.
@item
Updates and deletes that goes over multiple tables is harder to do in
@strong{MySQL}. (Will be fixed in @strong{MySQL} 4.0 with multi-table
@code{DELETE} and multi-table @code{UPDATE} and in @strong{MySQL} 4.1
with @code{SUB-SELECT})
@end itemize
The most important things that @code{PostgreSQL} supports that @strong{MySQL}
doesn't yet support:
PostgreSQL offers currently the following advantages over @strong{MySQL}:
@table @code
@item Sub select
@item Foreign keys
@item Stored procedures
@item An extendable type system.
@item A way to extend the SQL to handle new key types (like R-trees)
@end table
Note that because we know the @strong{MySQL} road map, we have included
in the following table the version when @strong{MySQL} should support
this feature. Unfortunately we couldn't do this for previous comparison,
because we don't know the PostgreSQL roadmap.
@strong{MySQL}, on the other hand, supports many ANSI SQL constructs
that @code{PostgreSQL} doesn't support. Most of these can be found at the
@uref{http://www.mysql.com/information/crash-me.php, @code{crash-me} Web page}.
@multitable @columnfractions .70 .30
@item @strong{Feature} @tab @strong{MySQL version}
@item Subselects @tab 4.1
@item Foreign keys @tab 4.0 and 4.1
@item Views. @tab 4.2
@item Stored procedures in multiple languages @tab 4.1
@item Extensible type system. @tab Not planed
@item Unions @tab 4.0.
@item Full join. @tab 4.0 or 4.1.
@item Triggers. @tab 4.1
@item Constrainst @tab 4.1
@item Cursors @tab 4.1 or 4.2
@item Extensible index types like R-trees @tab R-trees are planned to 4.2
@item Inherited tables @tab Not planned
@end multitable
If you really need the rich type system @code{PostgreSQL} offers and you
can afford the speed penalty of having to do everything transaction
safe, you should take a look at @code{PostgreSQL}.
Other reasons to use PostgreSQL:
@itemize @bullet
@item
Standard usage is in PostgreSQL closer to ANSI SQL in some cases.
@item
One can get speed up PostgreSQL by coding things as stored procedures.
@item
Bigger team of developers that contributes to the server.
@end itemize
Drawbacks with PostgreSQL compared to @strong{MySQL}:
@itemize @bullet
@item
@code{Vaccum()} makes PostgreSQL hard to use in a 24/7 environment.
@item
Only transactional tables.
@item
Much slower insert/delete/update.
@end itemize
For a complete list of drawbacks, you should also examine the first table
in this section.
@cindex PostgreSQL/MySQL, benchmarks
@node MySQL-PostgreSQL benchmarks, , MySQL-PostgreSQL features, Compare PostgreSQL
@subsection Benchmarking MySQL and PostgreSQL
The only open source benchmark, that we know of, that can be used to
benchmark @strong{MySQL} and PostgreSQL (and other databases) is our
own. It can be found at:
@uref{http://www.mysql.com/information/benchmarks.html}.
We have many times asked the PostgreSQL developers and some PostgreSQL
users to help us extend this benchmark to make the definitive benchmark
for databases, but unfortunately we haven't got any feedback for this.
We, the @strong{MySQL} developers, has because of this spent a lot of
hours to get maximum performance from PostgreSQL for the benchmarks, but
because we don't know PostgreSQL intimately we are sure that there are
things that we have missed. We have on the benchmark page documented
exactly how we did run the benchmark so that it should be easy for
anyone to repeat and verify our results.
The benchmarks are usually run with and without the @code{--fast}
option. When run with @code{--fast} we are trying to use every trick
the server can do to get the code to execute as fast as possible.
The idea is that the normal run should show how the server would work in
a default setup and the @code{--fast} run shows how the server would do
if the application developer would use extensions in the server to make
his application run faster.
When running with PostgreSQL and @code{--fast} we do a @code{vacuum()}
between after every major table update and drop table to make the database
in perfect shape for the following selects. The time for vacuum() is
measured separately.
When running with PostgreSQL 7.1.1 we could however not run with
@code{--fast} because during the insert test, the postmaster (the
PostgreSQL deamon) died and the database was so corrupted that it was
impossible to restart postmaster. (The details about the machine we run
the benchmark can be found on the benchmark page). After this happened
twice, we decided to postpone the @code{--fast} test until next
PostgreSQL release.
Before going to the other benchmarks we know of, We would like to give
some background to benchmarks:
It's very easy to write a test that shows ANY database to be best
database in the world, by just restricting the test to something the
database is very good at and not test anything that the database is not
good at; If one after this publish the result with a single figure
things is even easier.
This would be like we would measure the speed of @strong{MySQL} compared
to PostgreSQL by looking at the summary time of the MySQL benchmarks on
our web page. Based on this @strong{MySQL} would be more than 40 times
faster than PostgreSQL, something that is of course not true. We could
make things even worse by just taking the test where PostgreSQL performs
worst and claim that @strong{MySQL} is more than 2000 times faster than
PostgreSQL.
The case is that @strong{MySQL} does a lot of optimizations that
PostgreSQL doesn't do and the other way around. An SQL optimizer is a
very complex thing and a company could spend years on just making the
optimizer faster and faster.
When looking at the benchmark results you should look for things that
you do in your application and just use these results to decide which
database would be best suited for your application. The benchmark
results also shows things a particular database is not good at and should
give you a notion about things to avoid and what you may have to do in
other ways.
We know of two benchmark tests that claims that PostgreSQL performers
better than @strong{MySQL}. These both where multi-user tests, a test
that we here at @strong{MySQL AB} haven't had time to write and include in
the benchmark suite, mainly because it's a big task to do this in a
manner that is fair against all databases.
One is the benchmark paid for by
@uref{http://www.greatbridge.com/about/press.php?content_id=4,Great
Bridge}.
This is the worst benchmark we have ever seen anyone ever conduct. This
was not only tuned to only test what PostgreSQL is absolutely best at,
it was also totally unfair against every other database involved in the
test.
@strong{NOTE}: We know that not even some of the main PostgreSQL
developers did like the way Great Bridge conducted the benchmark, so we
don't blame them for the way the benchmark was made.
This benchmark has been condemned in a lot of postings and newsgroups so
we will here just shortly repeat some things that where wrong with it.
@itemize @bullet
@item
The tests where run with an expensive commercial tool, that makes it
impossible for an open source company like us to verify the benchmarks,
or even check how the benchmark where really done. The tool is not even
a true benchmark tool, but a application/setup testing tool. To refer
this as STANDARD benchmark tool is to stretch the truth a long way.
@item
Great Bridge admitted that they had optimized the PostgreSQL database
(with vacuum() before the test) and tuned the startup for the tests,
something they hadn't done for any of the other databases involved. To
say "This process optimizes indexes and frees up disk space a bit. The
optimized indexes boost performance by some margin". Our benchmarks
clearly indicates that the difference in running a lot of selects on a
database with and without vacuum() can easily differ by a factor of 10.
@item
The test results where also strange; The ASPAP3 test benchmark
documentation mentions that the test does:
"selections, simple joins, projections, aggregates, one-tuple updates,
and bulk updates"
PostgreSQL is good at doing selects and joins (especially after a
vacuum()), but doesn't perform as well on inserts/updates; The
benchmarks seem to indicate that only SELECTs where done (or very few
updates) . This could easily explain they good results for PostgreSQL in
this test. The bad results for MySQL will be obvious a bit down in this
document.
@item
They did run the so called benchmark from a Windows machine against a
Linux machine over ODBC, a setup that no normal database user would ever
do when running a heavy multi-user application. This tested more the
ODBC driver and the Windows protocol used between the clients than the
database itself.
@item
When running the database against Oracle and MS-SQL (Great Bridge has
indirectly indicated that the databases they used in the test),
they didn't use the native protocol but instead ODBC. Anyone that has
ever used Oracle, knows that all real application uses the native
interface instead of ODBC. Doing a test through ODBC and claiming that
the results had anything to do with using the database for real can't
be regarded as fair play. They should have done two tests with and
without ODBC to provide the right facts (after having got experts to tune
all involved databases of course).
@item
They refer to the TCP-C tests, but doesn't anywhere mention that the
tests they did where not a true TCP-C test and they where not even
allowed to call it a TCP-C test. A TCP-C test can only be conducted by
the rules approved by the @uref{http://www.tpc.org,TCP-council}. Great
Bridge didn't do that. By doing this they have both violated the TCP
trademark and miscredited their own benchmarks. The rules set by the
TCP-council are very strict to ensure that no one can produce false
results or make unprovable statements. Apparently Great Bridge wasn't
interested in doing this.
@item
After the first test, we contacted Great Bridge and mentioned to them
some of the obvious mistakes they had done with @strong{MySQL}; Running
with a debug version of our ODBC driver, running on a Linux system that
wasn't optimized for threads, using an old MySQL version when there was
a recommended newer one available, not starting @strong{MySQL} with the
right options for heavy multi-user use (the default installation of
MySQL is tuned for minimal resource use). Great Bridge did run a new
test, with our optimized ODBC driver and with better startup options for
MySQL, but refused to either use our updated glibc library or our
standard binary (used by 80% of our users), which was statically linked
with a fixed glibc library.
According to what we know, Great Bridge did nothing to ensure that the
other databases was setup correctly to run good in their test
environment. We are sure however that they didn't contact Oracle or
Microsoft to ask for their advice in this matter ;)
@item
The benchmark was paid for by Great Bridge, and they decided to publish
only partial chosen results (instead of publishing it all).
@end itemize
Tim Perdue, a long time PostgreSQL fan and a reluctant MySQL user
published a comparison on
@uref{http://www.phpbuilder.com/columns/tim20001112.php3,phpbuider}.
When we got aware of the comparison, we phoned Tim Perdue about this
because there was a lot of strange things in his results. For example,
he claimed that MySQL had a problem with five users in his tests, when we
know that there are users with similar machines as his that are using
MySQL with 2000 simultaneous connections doing 400 queries per second (In
this case the limit was the web bandwidth, not the database).
It sounded like he was using a Linux kernel that either had some
problems with many threads (Linux kernels before 2.4 had a problem with
this but we have documented how to fix this and Tim should be aware of
this problem). The other possible problem could have been an old glibc
library and that Tim didn't use a MySQL binary from our site, which is
linked with a corrected glibc library, but had compiled a version of his
own with. In any of the above cases, the symptom would have been exactly
what Tim had measured.
We asked Tim if we could get access to his data so that we could repeat
the benchmark and if he could check the MySQL version on the machine to
find out what was wrong and he promised to come back to us about this.
He has not done that yet.
Because of this we can't put any trust in this benchmark either :(
Conclusion:
The only benchmarks that exist today that anyone can download and run
against @strong{MySQL}and PostgreSQL is the MySQL benchmarks. We here
at @strong{MySQL} believe that open source databases should be tested
with open source tools! This is the only way to ensure that no one
does tests that none can reproduce and use this to claim that a
database is better than another. Without knowing all the facts it's
impossible to answer the claims of the tester.
The thing we find strange is that every test we have seen about
PostgreSQL, that is impossible to reproduce, claims that PostgreSQL is
better in most cases while our tests, which anyone can reproduce,
clearly shows otherwise. With this we don't want to say that PostgreSQL
isn't good at many things (It is!) We would just like to see a fair test
where they are very good so that we could get some friendly competition
going!
For more information about our benchmarks suite see @xref{MySQL
Benchmarks}.
We are working on even better benchmarks including much better
documentation (the current is lacking).
@cindex internals
@cindex threads
@ -44886,7 +45363,7 @@ html templates. By Alex Krohn.
This cgi scripts in Perl enables you to edit content of Mysql
database. By Tomas Zeman.
@item
@uref{http://futurerealm.com/opensource/futuresql.htm, FutureSQL Web Database Administration Tool}.
@uref{http://worldcommunity.com/opensource/futuresql, FutureSQL Web Database Administration Tool}.
FutureSQL by Peter F. Brown, is a free, open source rapid application
development Web database administration tool, written in Perl,
using @strong{MySQL}. It uses @code{DBI:DBD} and @code{CGI.pm}.
@ -45145,6 +45622,10 @@ Patches for @code{radiusd} to make it support @strong{MySQL}. By Wim Bonis,
@appendixsec Useful Tools
@itemize @bullet
@item @uref{http://worldcommunity.com/opensource/utilities/mysql_backup.html, MySQL Backup}.
A backup script for MySQL. By Peter F. Brown.
@item @uref{http://www.mysql.com/Downloads/Contrib/mytop, mytop}
@item @uref{http://public.yahoo.com/~jzawodn/mytop/, mytop home page}
mytop is a Perl program that allows you to monitor @strong{MySQL} servers by
@ -45862,6 +46343,15 @@ not yet 100% confident in this code.
@appendixsubsec Changes in release 3.23.39
@itemize @bullet
@item
If one dropped and added an @code{auto_increment} column, the
@code{auto_increment} value wasn't reset.
@item
Fixed problem where @code{LOCK TABLES table_name READ} followed by
@code{FLUSH TABLES} put a exclusive lock on the table.
@item
@code{REAL} @@variables with was represented with 2 digits when
converted to strings.
@item
Fixed problem that client 'hung' when @code{LOAD TABLE FROM MASTER} failed.
@item
Running @code{myisamchk --fast --force} will no longer repair tables
@ -51118,6 +51608,10 @@ Everything in this list is approximately in the order it will be done. If you
want to affect the priority order, please register a license or support us and
tell us what you want to have done more quickly. @xref{Licensing and Support}.
The plan is that we in the future will support the full ANSI SQL99
standard, but with a lot of useful extensions. The challenge is to do
this without sacrifying the speed or compromise the code.
@node TODO MySQL 4.0, TODO future, TODO, TODO
@appendixsec Things that should be in 4.0

2
isam/_dynrec.c
View File

@ -954,7 +954,7 @@ static int _nisam_cmp_buffer(File file, const byte *buff, ulong filepos, uint le
{
if (my_read(file,temp_buff,next_length,MYF(MY_NABP)))
goto err;
if (memcmp((byte*) buff,temp_buff,IO_SIZE))
if (memcmp((byte*) buff,temp_buff,next_length))
DBUG_RETURN(1);
buff+=next_length;
length-= next_length;

9
myisam/mi_dynrec.c
View File

@ -1221,20 +1221,19 @@ static int _mi_cmp_buffer(File file, const byte *buff, my_off_t filepos,
char temp_buff[IO_SIZE*2];
DBUG_ENTER("_mi_cmp_buffer");
VOID(my_seek(file,filepos,MY_SEEK_SET,MYF(0)));
next_length= IO_SIZE*2 - (uint) (filepos & (IO_SIZE-1));
while (length > IO_SIZE*2)
{
if (my_read(file,temp_buff,next_length,MYF(MY_NABP)))
if (my_pread(file,temp_buff,next_length,filepos, MYF(MY_NABP)) ||
memcmp((byte*) buff,temp_buff,next_length))
goto err;
if (memcmp((byte*) buff,temp_buff,IO_SIZE))
DBUG_RETURN(1);
filepos+=next_length;
buff+=next_length;
length-= next_length;
next_length=IO_SIZE*2;
}
if (my_read(file,temp_buff,length,MYF(MY_NABP)))
if (my_pread(file,temp_buff,length,filepos,MYF(MY_NABP)))
goto err;
DBUG_RETURN(memcmp((byte*) buff,temp_buff,length));
err:

2
myisam/mi_packrec.c
View File

@ -1010,7 +1010,7 @@ uint _mi_pack_get_block_info(MI_INFO *myisam, MI_BLOCK_INFO *info, File file,
{
ref_length=myisam->s->pack.ref_length;
/*
We can't use my_pread() here because mi_rad_pack_record assumes
We can't use my_pread() here because mi_read_rnd_pack_record assumes
position is ok
*/
VOID(my_seek(file,filepos,MY_SEEK_SET,MYF(0)));

5
mysql-test/r/alter_table.result
View File

@ -27,3 +27,8 @@ n
12
Table Op Msg_type Msg_text
test.t1 optimize status OK
i
1
2
3
4

4
mysql-test/r/variables.result
View File

@ -1,7 +1,7 @@
@test @`select` @TEST @not_used
1 2 3 NULL
@test_int @test_double @test_string @test_string2 @select
10 0.00 abcdeghi abcdefghij NULL
10 1e-10 abcdeghi abcdefghij NULL
@test_int @test_double @test_string @test_string2
hello hello hello hello
@test_int @test_double @test_string @test_string2
@ -10,3 +10,5 @@ hellohello hellohello hellohello hellohello
NULL NULL NULL NULL
@t1:=(@t2:=1)+@t3:=4 @t1 @t2 @t3
5 5 1 4
@t5
1.23456

11
mysql-test/t/alter_table.test
View File

@ -71,3 +71,14 @@ ALTER TABLE t1 ADD Column new_col int not null;
UNLOCK TABLES;
OPTIMIZE TABLE t1;
DROP TABLE t1;
#
# Drop and add an auto_increment column
#
create table t1 (i int unsigned not null auto_increment primary key);
insert into t1 values (null),(null),(null),(null);
alter table t1 drop i,add i int unsigned not null auto_increment, drop primary key, add primary key (i);
select * from t1;
drop table t1;

4
mysql-test/t/variables.test
View File

@ -1,7 +1,7 @@
#
# test variables
#
set @`test`=1,@TEST=3,@select=2;
set @`test`=1,@TEST=3,@select=2,@t5=1.23456;
select @test,@`select`,@TEST,@not_used;
set @test_int=10,@test_double=1e-10,@test_string="abcdeghi",@test_string2="abcdefghij",@select=NULL;
select @test_int,@test_double,@test_string,@test_string2,@select;
@ -12,3 +12,5 @@ select @test_int,@test_double,@test_string,@test_string2;
set @test_int=null,@test_double=null,@test_string=null,@test_string2=null;
select @test_int,@test_double,@test_string,@test_string2;
select @t1:=(@t2:=1)+@t3:=4,@t1,@t2,@t3;
select @t5;

6
mysys/my_pread.c
View File

@ -66,11 +66,11 @@ uint my_pread(File Filedes, byte *Buffer, uint Count, my_off_t offset,
my_filename(Filedes),my_errno);
}
if ((int) readbytes == -1 || (MyFlags & (MY_FNABP | MY_NABP)))
DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
DBUG_RETURN(MY_FILE_ERROR); /* Return with error */
}
if (MyFlags & (MY_NABP | MY_FNABP))
DBUG_RETURN(0); /* Ok vid l{sning */
DBUG_RETURN(readbytes); /* purecov: inspected */
DBUG_RETURN(0); /* Read went ok; Return 0 */
DBUG_RETURN(readbytes); /* purecov: inspected */
}
} /* my_pread */

2
sql-bench/Makefile.am
View File

@ -23,7 +23,7 @@ bench_SCRIPTS = test-ATIS test-connect test-create test-insert \
test-big-tables test-select test-wisconsin \
test-alter-table graph-compare-results \
bench-init.pl compare-results run-all-tests \
server-cfg crash-me copy-db \
server-cfg crash-me copy-db
CLEANFILES = $(bench_SCRIPTS)
EXTRA_SCRIPTS = test-ATIS.sh test-connect.sh test-create.sh \
test-insert.sh test-big-tables.sh test-select.sh \

2
sql/item_func.cc
View File

@ -1758,7 +1758,7 @@ Item_func_get_user_var::val_str(String *str)
return NULL;
switch (entry->type) {
case REAL_RESULT:
str->set(*(double*) entry->value);
str->set(*(double*) entry->value,decimals);
break;
case INT_RESULT:
str->set(*(longlong*) entry->value);

3
sql/share/swedish/errmsg.OLD
View File

@ -206,3 +206,6 @@
"Kunde inte starta en tråd för replikering",
"Användare '%-.64s' har redan 'max_user_connections' aktiva inloggningar",
"Du kan endast använda konstant-uttryck med SET",
"Lock wait timeout exceeded",
"The total number of locks exceeds the lock table size",
"Update locks cannot be acquired during a READ UNCOMMITTED transaction",

3
sql/sql_base.cc
View File

@ -389,6 +389,9 @@ bool close_cached_tables(THD *thd, bool if_wait_for_refresh,
thd->in_lock_tables=1;
result=reopen_tables(thd,1,1);
thd->in_lock_tables=0;
/* Set version for table */
for (TABLE *table=thd->open_tables; table ; table=table->next)
table->version=refresh_version;
}
VOID(pthread_mutex_unlock(&LOCK_open));
if (if_wait_for_refresh)

1
sql/sql_insert.cc
View File

@ -1362,6 +1362,7 @@ select_create::prepare(List<Item> &values)
if (info.handle_duplicates == DUP_IGNORE ||
info.handle_duplicates == DUP_REPLACE)
table->file->extra(HA_EXTRA_IGNORE_DUP_KEY);
table->file->deactivate_non_unique_index((ha_rows) 0);
DBUG_RETURN(0);
}

9
sql/sql_table.cc
View File

@ -1233,7 +1233,16 @@ int mysql_alter_table(THD *thd,char *new_db, char *new_name,
{
if (drop->type == Alter_drop::COLUMN &&
!my_strcasecmp(field->field_name, drop->name))
{
/* Reset auto_increment value if it was dropped */
if (MTYP_TYPENR(field->unireg_check) == Field::NEXT_NUMBER &&
!(create_info->used_fields & HA_CREATE_USED_AUTO))
{
create_info->auto_increment_value=0;
create_info->used_fields|=HA_CREATE_USED_AUTO;
}
break;
}
}
if (drop)
{