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
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