Rewrite/re-arrange of "How stable is MySQL?" section, as per Monty/Kaj request.

@cindex stability

This section addresses the questions ``How stable is MySQL?'' and 

``Can I depend on MySQL in this project?''  We will try to clarify

some issues and to answer some of the more important questions that seem to 

concern many people.  This section has been put together from information 

gathered from the mailing list (which is very active in reporting bugs).

At TcX, the predecessor of MySQL AB, MySQL has worked without any problems in

projects since mid-1996. Original code stems back from the early 80s,

providing a table code base, and the ISAM table format remains backwards

compatible.  When MySQL was released to a wider public, we noticed that there

were some pieces of ``untested code'' that were quickly found by the new users

who made queries in a manner different than our own.  Each new release has had

fewer portability problems than the previous one (even though each has had

many new features).

Each release of MySQL has been usable, and there have been problems

only when users start to use code from the ``gray zones.''  Naturally, outside

users don't know what the gray zones are; this section attempts to indicate

those that are currently known.  The descriptions deal with Version 3.23

of MySQL.  All known and reported bugs are fixed in the latest 

version, with the exception of the bugs listed in the bugs section, which 

are things that are design-related.  @xref{Bugs}.

MySQL is written in multiple layers and different independent modules.

Some of the new modules are listed below with an indication of how

well-tested each of them is:

This section addresses the questions ``@emph{How stable is MySQL?}''

and ``@emph{Can I depend on MySQL in this project?}''

We will try to clarify these issues and answer some important

questions that concern many potential users. The information in this

section is based on data gathered from the mailing list, which is

very active in identifying problems as well as reporting types of use.

Original code stems back from the early 80s, providing a stable code

base, and the ISAM table format remains backwards compatible.

At TcX, the predecessor of MySQL AB, MySQL has worked in projects

since mid-1996, without any problems.

When MySQL was released to a wider public, we noticed that there were

some pieces of ``untested code'' that were quickly found by the new

users who made different types of queries from us. Each new release

has had fewer portability problems (even though each new release has

had many new features).

Each release of MySQL has been usable. There have only been problems

when users try code from the ``gray zones.''  Naturally, new users

don't know what the gray zones are; this section attempts to indicate

those that are currently known.

The descriptions mostly deal with Version 3.23 of MySQL.

All known and reported bugs are fixed in the latest version, with the

exception of those listed in the bugs section, which are things that

are design-related.  @xref{Bugs}.

MySQL design is multi-layered with independent modules. Some of the

newer modules are listed below with an indication of how well-tested

each of them is:

@cindex modules, list of

@table @strong

@item Locking --- Gamma

This is very system-dependent.  On some systems there are big problems

using standard OS locking (@code{fcntl()}).  In these cases, you should run the

MySQL daemon with the @code{--skip-locking} flag.  Problems are known

to occur on some Linux systems, and on SunOS when using NFS-mounted file

systems.

@item @strong{MyODBC 2.50} (uses ODBC SDK 2.5) --- Gamma

It seems to work well with some programs.

@item Replication -- Gamma

We are still working on replication, so don't expect this to be rock

solid yet.  On the other hand, some MySQL users are already

using this with good results.

@item BDB Tables -- Gamma

The Berkeley DB code is very stable, but we are still improving the interface

between MySQL and BDB tables, so it will take some time before this

is tested as well as the other table types.

@item InnoDB Tables -- Gamma

This is a recent addition to @code{MySQL}. They appear to work well and

can be used after some initial testing.

@item Automatic recovery of MyISAM tables - Gamma

This only affects the new code that checks if the table was closed properly

on open and executes an automatic check/repair of the table if it wasn't.

@item FULLTEXT -- Beta

Text search seems to work, but is still not widely used.

@item Bulk-insert - Alpha

Large server clusters using replication are in production use, with

good results. Work on enhanced replication features is continuing

in MySQL 4.0.

@item @code{InnoDB} tables -- Gamma

While the @code{InnoDB} transactional table handler is a fairly recent

addition to @code{MySQL}, it appears to work well and is already being

used in some large, heavy load production systems.

@item @code{BDB} tables -- Gamma

The @code{Berkeley DB} code is very stable, but we are still improving

the @code{BDB} transactional table handler interface in MySQL, so it

will take some time before this is as well tested as the other table

types.

@item @code{FULLTEXT} -- Beta

Full text search works but is not yet widely used.

Important enhancements are being implemented for MySQL 4.0.

@item @code{MyODBC 2.50} (uses ODBC SDK 2.5) -- Gamma

Increasingly in wide use. Some issues brought up appear to be

application related and independent of the ODBC driver or underlying

database server.

@item Automatic recovery of @code{MyISAM} tables -- Gamma

This status only regards the new code in the @code{MyISAM} table

handler that checks if the table was closed properly on open and

executes an automatic check/repair of the table if it wasn't.

@item Bulk-insert -- Alpha

New feature in MyISAM in MySQL 4.0 for faster insert of many rows.

@item Locking -- Gamma

This is very system-dependent.  On some systems there are big problems

using standard OS locking (@code{fcntl()}).  In these cases, you should

run @code{mysqld} with the @code{--skip-locking} flag.

Problems are known to occur on some Linux systems, and on SunOS when

using NFS-mounted file systems.

@end table

MySQL AB provides high-quality support for paying customers, but the 

MySQL mailing list usually provides answers to common questions.

Bugs are usually fixed right away with a patch; for serious bugs, there is

almost always a new release.

Bugs are usually fixed right away with a patch; for serious bugs,

there is almost always a new release.

@node Table size, Year 2000 compliance, Stability, What-is