
2020-12-31  Ron Norman <rjn@inglenet.com>

	* vbisam.h: Changes to be more compatible with C-ISAM 

2020-12-27  Simon Sobisch <simonsobisch@gnu.org>

	* Makefile.am: cleanup and comments
	* missing: updated from GnuCOBOL 3.1.2
	* pycompile: removed as unused
	* general: moved additional build-scripts to build_aux, updated from
	  https://git.savannah.gnu.org/cgit/gnulib.git/tree/build-aux/
	* build-aux/bootstrap, autogen.sh: added adjusted versions,
	  originating in GnuCOBOL 3.1.2
	* configure.ac: added AC_CONFIG_AUX_DIR([build_aux])
	* configure.ac: copied some parts from GnuCOBOL including
	  --enable-debug and --enable-hardening, removed AM_MAINTAINER_MODE
	* configure.ac: new automake conditional CISAM_MODE to adjust library
	  name to libvbcisam, which is done together with renaming the installed
	  binaries to vbccheck and vbcrecover
	* configure.ac: bumped version to 2.2

2020-11-13  Ron Norman <rjn@inglenet.com>

	* Changes to have --with-compatcisam actually use C-ISAM compatible format

2014-09-06  Ron Norman <rjn@inglenet.com>

	* Added NULLKEY to vbisam.h
	* The character to be tested is put into top byte of keydesc.kp_type
	  so code referencing kp_type needs to do & BYTEMASK
	  Changes to isread.c and ischeck.c to use BYTEMASK
	  Changes to vbkeysio.c in the routine ivbkeyinsert to check for NULLKEY
	  then scan key value and if NULL do not insert to that index
	  Changes to isbuild to save NULLKEY char to disk and isopen to read it
	  back, Also ischeck to report how it was set.
	* Change isrecnum to type 'long', keydesc.k_rootnode & dictinfo.di_nrecords
	  to 'unsigned long' to match C-ISAM & D-ISAM structure formats
	  Change vbisam_off_t from 'int' to 'unsigned long' to allow for more
	  records in a file when compiled in 64 bit mode.
	  Some function headers changed to match the prototype defined in vbisam.h
	  and changes made so function prototypes also match C-ISAM/D-ISAM
	  functions.

2008-10-26  Cobol-IT

	* configure.ac: added -enable-thread-safe, --with-pthread
	* configure.ac: bumped version to 2.1.1

2007-11-27  Roger While <simrw@sim-basis.de>

	* Tidy code, take out caching mevhanism.

2007-02-26  Roger While <simrw@sim-basis.de>

	* 2.0 release. First release of libtoolized version.
	  We now have 3 extra directories : bin, tests, libvbisam.
	  The VBISAM library proper is in libvbisam. The helper
	  programs are in bin. Test programs are in tests.

	  Release version is defined in configure.ac

2004-06-07  Trevor van Bremen

1.03
====
Fixes list
----------
vbDataIO.c isinternal.h Makefile:
	Mikhail pointed out that VBISAM was illegally perform pointer arithmetic
	on voids within vbDataIO.c.  I'd thought the gcc switch -Wall would trap
	such things but I was wrong!  Added -Wpointer-arith to Makefile CFLAGS
isinternal.h:
	Mikhail added the correct values for VB_ENDIAN on HPUX and AIX.  I've
	requested Mikhail to check whether his compilers have a CPU-dependant
	manifest constant defined rather than an OS dependant one.
isopen.c:
	Guido pointed out that I was still using the OLD free list format in
	the tCountRows() function.  This was screwing up the returned value
	for the isindexinfo() call!
vbIndexIO.c vbCheck.c:
	Guido ALSO pointed out that C-ISAM is not 100% C-ISAM compatible in that
	it occassionally 'forgets' to insert the 0x7f in the free-list node
	signature. <Sigh>
CvtTo64.c Makefile isHelper.c isbuild.c isinternal.h isopen.c vbCheck.c vbDataIO.c vbIndexIO.c vbKeysIO.c vbNodeMemIO.c vbVarLenIO.c vbisam.h:
	Changed the dependency on _FILE_OFFSET_BITS == 64 to ISAMMODE == 1
	This is to allow the 64-bit file I/O system calls to function even when
	working on C-ISAM compatible file formats thus breaking the 31-bit (2GB)
	barrier and extending it to 41-bit!
vbCheck.c:
	Fixes made such that all that's required for a successful rebuild of a
	fixed length row file is the key descriptor nodes in the index file to
	be 'valid'.
	Also, set the index map entry for the dictionary node AFTER it may have
	been squashed.
istrans.c:
	A quick check of strace() output showed that C-ISAM is performing some
	rudimentary locking each time it writes to the transaction log file.
	I implemented the same scheme for compatibility.
vbLocking.c vbLowLevel.c:
	Changes made to iVBLock to directly deal with being interrupted by a
	signal during the fcntl call.
vbLocking.c:
	Made certain that the psKeyCurr[MAXSUBS] of a table are 'valid' within
	iVBEnter().
isdelete.c:
	Tidyup in preparation for 2PC (iProcessDelete function added)
	Handle correct error return for isdelrec+isdelcurr if row isn't on file
	Don't try to reinsert a key if iVBKeyDelete fails, it only corrupts the
	file further.  This should be done INSIDE iVBKeyDelete!
vbCheck.c:
	Fixup to correctly 'free' all that was allocated
vbNodeMemIO.c:
	If an index had LCOMPRESS but did not have TCOMPRESS, the high value
	entry in a node would still contain the TCOMPRESS count! (Ooops)
vbNodeMemIO.c vbKeysIO.c isinternal.h:
	I noticed that C-ISAM outperformed VBISAM if the index didn't
	make use of LCOMPRESS, TCOMPRESS or DCOMPRESS.  I surmized that in
	that case, C-ISAM is simply editing the key within the node rather than
	completely rebuilding the node from a linked list.  I've implemented
	a corresponding algorithm (iQuickNodeSave) in this module to bring
	VBISAM into the lead again (performance wise).  I'm guessing that many/
	most savvy C-ISAM developers always use SOME form of key compression and
	thus, this will PROBABLY not affect most people, but I could not BEAR
	the humiliation of some 25 year old piece of mature code outperforming
	my 6 month old creation.
	For anyone even MILDLY interested, the biggest performance gains in
	VBISAM can be made in the following functions:
		iVBNodeSave
		iVBTreeLoad
		iVBKeyCompare
		iVBKeyInsert
		iVBKeyDelete
	These currently consume the MAJORITY of CPU time and thus even a 'small'
	improvement in these functions can reap potentially disparate (large)
	benefit to overall throughput.
vbNodeMemIO.c:
	Fixes to 'force' the iIsTOF and iIsEOF flags within the tree
isHelper.c:
	a: Initialize tValue to 0 in ldquad and lValue to 0 in ldlong
	b: Globally reverse the VB_ENDIAN content to match BYTE_ORDER
isbuild.c:
	isaddindex was not returning an error if the table was not open in
	ISEXCLLOCK mode but still did not create the new index
MVTest.c:
	Extended to handle multiple indexes
	Decided to make rowlen 256 bytes too!
README.64bit:
	New file to describe some background for 64 bit operation
isrecover.c:
	Include error checking for call to iVBRollMeBack
iswrite.c:
	This was writing an INCORRECT transaction on fixed length files until
	isreclen got set.  Oops!
vbBlockIO.c:
	Standardized all file offsets as long long (64 bit)
vbKeysIO.c:
	Added in a couple of extra 'checking' algorithms for DEBUG use
	Largely rewrote the entire iVBKeyDelete function
vbMemIO.c:
	Added a few assertions on VBTREE / VBKEY (de-)allocation
isread.c:
	Guido pointed out that I wasn't setting iResult after iVBDataLock and
	was therefore returning JUNK
vbNodeMemIO.c:
	The new iQuickNodeSave function was not handling keys with ISDUPS set
vbKeysIO.c:
	iVBKeyLocateRow was not recursing through all the possible duplicates
	in order to find an EXACT match on the row number!
isinternal.h isopen.c isbuild.c vbLowLevel.c:
	Moved from using access(2) to using stat(2).
vbLowLevel.c isbuild.c isopen.c isinternal.h vbCheck.c:
	Implement the 'sharing' of open file handles since the close() call
	implicitly releases *ALL* locks on the handle that were 'owned' by the
	process.  Changes made to insert a level of indirection on:
		Open, Close, Lseek, Read, Write, Lock
isinternal.h isHelper.c isopen.c vbLocking.c:
	Moved the locks from psVBFile to sVBFile and implemented table-granular
	locking.  Note that if CISAMLOCKS is defined when compiling VBISAM, the
	locking strategy tries to more closely mirror that of C-ISAM.  However,
	this introduces BUGS just like in C-ISAM!  I advise against using the
	CISAMLOCKS and would PREFER you fixed the buggy code you have!
isopen.c:
	Minor fixup to delay setting psVBFile handles et al to -1
	(Was screwing up the freeing of locks!)
isinternal.h isHelper.c isdelete.c isread.c istrans.c vbLocking.c iswrite.c isrewrite.c:
	Change locking strategy to eliminate the concept of a 'transactional'
	lock.  ALL locks are transactional if VBISAM has called isbegin()!
iswrite.c:
	Only unlock a row if a transactional lock was applied *AND* the iswrite
	is going to FAIL!
vbKeysIO.c:
	Changes to keep psVBFile [iHandle]->psKeyCurr [iKeyNumber] up to date on
	iVBKeyDelete() calls.
	Changes to the debug routines
	Fix iVBLocateRow (was NFG if ISDUPS was set!)
isrewrite.c:
	Changes to make iRowUpdate work correctly for ISDUPS indexes
vbLocking.c:
	Changes to iVBEnter such that it will FAIL with ENOTRANS if isbegin was
	not called PRIOR to the VBISAM function that is calling iVBEnter.
isdelete.c:
	Make writing the log transation the LAST function!
	Also, use pcWriteBuffer for the deleted row so the log WORKS
vbNodeMemIO.c:
	TINY change to delay resetting iIsTOF in iNodeSplit since it was being
	screwed up by iVBNodeSave
isrewrite.c:
	OK, let's face it. It was a MESS (Still is, but it worx lotz betta!)
isopen.c:
	isindexinfo was returning an INCORRECT di_nrecords!
Known Issues
------------
Uncertain (but MOSTLY in vbKeysIO.c):
	Two-phase commit (2PC) still needs to be done
vbLowLevel.c:
	I believe that incoming signals are still an issue on at least the
	tVBRead () function.
	(write() *SHOULD* be atomic already but I know that read() is not)
vbCheck.c:
	Still not able to process ISVARLEN files
	Since vbCheck doesn't call iVBExit until it's finished all its work, it
	becomes a REAL memory hog!  (See vbMemIO.c below)
vbMemIO.c:
	More of a 'suggestion' than an 'issue'.  It's probably wise to 'limit'
	the amount of RAM any given VBISAM process can allocate.  An environment
	variable would be the logical way to do this.  Also, it'd might be cool
	to make it so that you could allow a maximum of X bytes per table with
	an overall limit of Y bytes for the process as a whole.
Documentation:
	Heck, I need to write a whole freaking BOOK!!!
	Reminder to self to include the environment variables in the docs
================================================================================
06Jun2004 1.02-beta (D-Day!)
============================
Fixes list
----------
LOTS of changes!!! (Certain that I've NOT covered them all here)

iswrite() was creating a row in the data file BEFORE having created the index
entries associated with it.  If an EDUPL error resulted, the data row was not
purged.  Fixed by delaying writing the data row till AFTER the indexes were
added.

Management of the data row free lists was a mess.  Previously deleted data rows
were *not* being reused.

Interprocess disturbances causing 105 (EBADFILE) errors were common during
iswrite () and iscommit () operations

Using the same transaction log file for multiple processes was causing 105
(EBADFILE) errors

iswrite was inserting a new row into the *WRONG* node if it was exactly
replacing a row that had previously been deleted. (Including the dup number)

iVBEnter () and iVBExit () code fixed to better handle concurrency
(Most specifically, the handling of the iIsDictLocked to determine whether the
iVBExit () call should update the dictionary node transaction number)
Many source modules modified to change handling of iIsDictLocked.

Minor 'touch ups' made to the internal cache handling functions iVBBlockXXXX()
Also, externalized them into their own unique module (vbBlockIO.c) with a switch
possible in isinternal.h to allow selection of caching. (VB_CACHE)

Bug fixed where performing an isread (ISEQUAL) on a table where the index was
ISDUPS would NOT find any matching rows if the FIRST (duplicate number 0) row
of that key value had been deleted.

I re-tested the suite 'performance' again (Thank goodness for strace) to
see what else could be optimized...
In doing so, I found a HUGE saving in the TreeLoad function.
Instead of searching the linked-list of keys in the VBTREE structure, I
implemented a simple array of keys and devised a crude but effective list
bi-section algorithm.  VBISAM now beats the pants off the competition!
It's possible that I can optimize this even further and, based
upon the DRAMATIC improvements it's offered thus far, I will probably do so.
Also, I need to phase out the old use of the psKeyFirst and psKeyLast values
held in the VBTREE structure.

Fixed up the isrecover () code to truly recover things as it should!

Wrote a simple program (vbRecover) that performs the actual isrecover given the
name of the log file on the command line

Wrote the beginnings of the VBISAM equivalent to bcheck as vbCheck

Known Issues
------------
STILL have not bothered to write iscluster ()
I simply CANNOT see enough relevance to do so

STILL have not bothered to write isaudit ()
Does *ANYONE* out there really USE this?

Need to test the functionality of deleting a row within a transaction...
Should it be possible for an unrelated process to create a row with the SAME
unique index values before the transaction has been 'committed'?
Interestingly enough, C-ISAM Vn 7.2 fails MISERABLY on this issue to the point
where the DataFree list in the index file becomes corrupted.
See the bug files on SF.net titled "When is a bug NOT a bug?"
Note for self to fully implement ACID within VBISAM
This is in the process of being addressed by way of the 2PC (Two Phase Commit)
but is NOT fully implemented in this release!
A strong CAVEAT with respect to the 2PC code is that the index file of a given
table will be left in an inconsistent state for much longer periods than the
competition.  Specifically, any key deletion will *NOT* take effect until the
transaction is completed with an isrollback or iscommit call.  A system-crash
occuring during a transaction thus leaves the index file a little 'screwed up'.
However, the vbCheck and isrecover system of VBISAM automagically deals with
this issue.  Furthermore, it is always good programming practice to make any
transaction as short as possible (thereby minimizing the effect) and it's also
good practice to at least vbCheck (if not completely recover) the effected
tables subsequent to a system crash.

Need to fully test the row release code in isHelper.c (isrelease, isrelrec and
isrelcurr).  Specifically, I want to make sure that they are 'transaction-safe'

Many function calls are still made without testing the return value.  Most of
these are flagged in the source with a comment containing the word 'BUG'.

Still need to 'complete' the isrecover code to handle the following transaction
types:
	VBL_BUILD, VBL_CREINDEX, VBL_DELINDEX, VBL_CLUSTER
	VBL_FILEERASE, VBL_RENAME, VBL_SETUNIQUE, VBL_UNIQUEID

Still haven't implemented the virtual file system.  If I bother at all with
doing so, it will come *AFTER* the 2PC code.

With all the changes made in this release, I've not yet ascertained whether the
64-bit file I/O is fully functional.  I have no specific reason to suspect to
the contrary, but YMMV.  Let me know if you encounter any issues.

Summary
-------
All in all, quite a valuable release this time IMNSHO. Give it a few weeks time
to allow things to 'settle' and I'll seriously consider moving the SF.net status
of VBISAM from BETA to whatever comes next...
As always, many thanks to those in the virtual OSS world who have assisted me
to 'polish' VBISAM to its current state.  Feature requests are *ALWAYS* welcome
================================================================================
06Jan2004 1.01Beta
==================
Added COPYING.LIB and License line to each module header
(Thanks to Johann von Nepomuk for spotting this huge oversight on my part!)

Changed VBBLOCK based functions in vbLowLevel.c to delay writing back to the
disk files while the index is 'locked' for use.  (Limits the number of system
calls performed.  This *REALLY* has a HUGE impact if ISEXCLLOCK is used!

Implemented variable length row processing
HUGE warning...  This is not 100% compatible with the competition from IBM.
Therefore, if you use the bcheck utility from IBM, it *MAY* report issues with
the variable length nodes in the index file.  This is because the IBM product
uses a *STUPID* algorithm for determining which 'group' a variable length node
with some free space left should belong to.  (Namely, IBM appears to have
cutoffs at 200-bytes, 400-bytes, 600-bytes and 800-bytes.  I have chosen to use
a logarithmic approach instead with cutoffs at 8-bytes, 32-bytes, 128-bytes and
512-bytes).  To put it MILDLY, the varlen code should be considered 'UNSTABLE'
in this release.
