-/*
- * Copyright (c) 1996-1998, Index Data.
- * See the file LICENSE for details.
- * Heikki Levanto
- *
- * $Id: merge-d.c,v 1.27 2002-07-12 18:12:21 heikki Exp $
- *
- * bugs
- * sinleton-bit has to be in the high end, not low, so as not to confuse
- * ordinary small numbers, like in the next pointer..
- *
- * missing
- *
- * optimize
- * - study and optimize block sizes (later)
- * - find a way to decide the size of an empty diffblock (after merge)
- * - On allocating more blocks (in append and merge), check the order of
- * blocks, and if needed, swap them.
- * - Write a routine to save/load indexes into a block, save only as many
- * bytes as needed (size, diff, diffindexes)
- *
- *
- * caveat
- * There is a confusion about the block addresses. cat or type is the category,
- * pos or block is the block number. pp structures keep these two separate,
- * and combine when saving the pp. The next pointer in the pp structure is
- * also a combined address, but needs to be combined every time it is needed,
- * and separated when the partss are needed... This is done with the isamd_
- * _block, _type, and _addr macros. The _addr takes block and type as args,
- * in that order. This conflicts with the order these are often mentioned in
- * the debug log calls, and other places, leading to small mistakes here
- * and there.
- *
- * Needs cleaning! The way diff blocks are handled in append and reading is
- * quite different, and likely to give maintenance problems.
- *
- * log levels (set isamddebug=x in zebra.cfg (or what ever cfg file you use) )
- * 0 = no logging. Default
- * 1 = no logging here. isamd logs overall statistics
- * 2 = Each call to isamd_append with start address and no more
- * 3 = Start and type of append, start of merge, and result of append
- * 4 = Block allocations
- * 5 = Block-level operations (read/write)
- * 6 = Details about diff blocks etc.
- * 7 = Log each record as it passes the system (once)
- * 8 = Log raw and (de)coded data
- * 9 = Anything else that may be useful
- * .. = Anything needed to hunt a specific bug
- * (note that all tests in the code are like debug>3, which means 4 or above!)
- *
- * Design for the new and improved isamd
- * Key points:
- * - The first block is only diffs, no straight data
- * - Additional blocks are straight data
- * - When a diff block gets filled up, a data block is created by
- * merging the diffs with the data
- *
- * Structure
- * - Isamd_pp: buffer for diffs and for data
- * keep both pos, type, and combined address
- * routine to set the address
- * - diffbuf: lengths as short ints, or bytes for small blocks
- * - keys are of key_struct, not just a number of bytes.
- *
- * Routines
- * - isamd_append
- * - create_new_block if needed
- * - append_diffs
- * - load_diffs
- * - get diffend, start encoding
- * - while input data
- * - encode it
- * - if no room, then realloc block in larger size
- * - if still no room, merge and exit
- * - append in the block
- *
- * - merge
- * - just as before, except that merges also input data directly
- * - writes into new data blocks
- *
- *
- * - isamd.c: load firstpp, load datablock
- * save firstpp, save datablock
- * - Readlength, writelength - handling right size of len fields
- * - isamd_read_main_item: take also a merge input structure, and merge it too
- * - prefilter: cache two inputs, and check if they cancel.
- * - single-item optimization
- *
- * questions: Should we realloc firstblocks in a different size as the main
- * blocks. Makes a sideways seek, which is bound to be slowe. But saves some
- * update time. Compromise: alloc the first one in the size of the datablock,
- * but increase if necessary. Large blocks get a large diff, ok. Small ones
- * may get an extra seek in read, but save merges.
- */
+/* $Id: merge-d.c,v 1.28 2002-08-02 19:26:56 adam Exp $
+ Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002
+ Index Data Aps
+
+This file is part of the Zebra server.
+
+Zebra is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+Zebra is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with Zebra; see the file LICENSE.zebra. If not, write to the
+Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.
+*/
+
+
#define NEW_ISAM_D 1 /* not yet ready to delete the old one! */
/*
* $Log: merge-d.c,v $
- * Revision 1.27 2002-07-12 18:12:21 heikki
+ * Revision 1.28 2002-08-02 19:26:56 adam
+ * Towards GPL
+ *
+ * Revision 1.27 2002/07/12 18:12:21 heikki
* Isam-D now stores small entries directly in the dictionary.
* Needs more tuning and cleaning...
*
projects / idzebra-moved-to-github.git / blobdiff