sqlite

SQLite is a Self-contained, embeddable, zero-configuration SQL database
engine. For information about SQLite, see the main README or check the
site here: http://www.sqlite.org

This is the Amiga version of sqlite-3.34.0 and can be considered stable.
The regression tests either succeed without failure or reported errors can 
be explained or document limitations of this version.  See below for a list
of limitations in the Amiga version.

There have been several attempts to port SQLite to AmigaOS.  Please browse
Aminet for a list.  Several of the previous ports made use of the Posix/
ixemul interface that provides a Unix-like emulation of what is needed by
the SQLite low level file access.

This port is different in that it only uses AmigaOS 3 native functions
for implementing the OS interface.  The changes to the original version
are in writing a custom Makefile for Amiga, implementing the OS module 
for AmigaOS, adding some work-around for char to 64bit integer conversion
bugs in the gcc-3.4.0 compiler, and making some other minor changes in 
several files.  A complete diff of all changes can be found in the file 
amiga-diff.txt.

Note that this version fully supports 64bit integers.  This, however, 
requires a compiler that supports 64bit integers and rules out, e.g. SAS-C.

The os_amiga.c file contains an implementation of all necessary OS functions.
This module was written by taking os_unix.c as a start, looking at os_win.c 
sometimes to get an idea on how else things can be done, by careful reading 
the autodocs of AmigaDOS, by testing some of the more advanced functions in 
AmigaDOS 3.0+ (e.g. LockRecord which seems to be unimplemented on most 
filesystems), and by running the regression tests and tweaking the code
to ensure a correct implementation.  If you are interested, you can find 
many comments in os_amiga.c, in particular about how to do the file locking.

The library and the sqlite3 shell have been compiled for m68k-AmigaOS
using gcc-3.4.0.  The compiled binaries can be found in build-m68k-amigaos.
The binaries also contain the 'testfixture' program for running 
the regression test suite.  As 'testfixture' needs a tcl interpreter, 
I ported tcl-8.6.10 to AmigaOS using the ixemul library interface and 
also compiled 'testfixture' against it.  Note that the sqlite3 shell and 
libraries are compiled with the -noixemul switch and are thus are true 
'Amiga-like' binaries.

There are also AmigaOS 4 binaries under directory build-ppc-amigaos,
MorphOS binaries under directory build-ppc-morphos, and i386 AROS binaries
under directory build-i386-aros.

The regression tests have been run for the AmigaOS 3 version (under UAE).
Test results for MorphOS are also available and are similar 
to the results on Amiga OS3 but haven't been fully analyzed yet.

Limitations

- No support for large files (LFS).  To the best of my knowledge files
  under AmigaOS can be at most (2**31 - 1) bytes.  This limitation arises
  from the LONG parameters in dos.library.
  Compile switch -DSQLITE_DISABLE_LFS
  (AOS4 and MorphOS introduce support for large files and implementation is
  in progress).
  
- No byte-range-locking.  I tried several file systems (OFS, FFS) but they
  do not seem to support the LockRecord/UnLockRecord calls (The RAM: disk
  does support it and maybe SFS also has it implemented).  Therefore, the
  default way of locking is by using (several) .lock files.  Read os_amiga.c
  if you want to know more about this.

- Truncate file by replace.  The dos.library/SetFileSize call is unsupported
  by most file systems (OFS, FFS) and therefore truncating a file to a
  target size doesn't work.  My workaround to this is to write a new file
  of the target size and replace the files.  This does not always work
  though if the file is still opened by another process/handle.  In this
  case truncating fails which means that the 'VACUUM' command of sqlite
  fails.  Use a file system that supports SetFileSize (try SFS) if you need
  to rely on a proper functioning of the VACUUM command.

- No load extensions.  On Amiga the shared loading of libraries works very
  differently than on Unix, and thus, no attempt has been made to support it.

- No WAL (Write-Ahead Logging) mode.

- Several errors in unit tests remain.  See build-m68k-amigaos/test-out.txt
  for a full list.  Most of the errors can be categorized into one of
  rounding error on double, representation of double, stat on an open file,
  ixemul vs. AmigaDOS paths, delete on an open file, or other unsupported
  system functions (e.g. spawning a new process).

  You can reproduce results by running 'testfixture ../test/veryquick.test'.
  Prior to running this test, make sure the stack is at least 500kBytes large
  as the tcl interpreter uses a lot of stack in recursive calls.

Steffen Gutmann, 24.01.2021