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7081f2a58e
Implement an improved binlog implementation that is integrated into the storage engine. The new implementation is enabled with the --binlog-storage-engine option. Initially the InnoDB storage engine implements the binlog. Integrating the binlog in the storage engine improves performance, since it makes the InnoDB redo log the single source of truth and avoids the need for expensive two-phase commit between binlog and engine. It also makes it possible to disable durability (set --innodb-flush-log-at-trx-commit=0) to further improve performance, while still preserving the ability to recover the binlog and database into a consistent state after a crash. The new binlog implementation also greatly improves the internal design and implementation of the binlog, and enables future enhancements for replication. This is a squash of the original 11.4-based patch series. Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
73 lines
2.6 KiB
C++
73 lines
2.6 KiB
C++
/*****************************************************************************
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Copyright (c) 2024 Kristian Nielsen.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
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*****************************************************************************/
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/*
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Reading and writing of compressed integers.
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Created 2024-10-01 Kristian Nielsen <knielsen@knielsen-hq.org>
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*/
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#ifndef MY_COMPR_INT_H
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#define MY_COMPR_INT_H
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#include "my_bit.h"
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#include <stdint.h>
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#include <utility>
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/*
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Read and write compressed (up to) 64-bit integers.
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A 64-bit number is encoded with 1-9 bytes. The 3 first bits stores a tag
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that determines the number of bytes used, and the encoding is written in
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little-endian format as (TAG | (NUMBER << 3)). The tag is the number of
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bytes used minus 1, except that 7 denotes 9 bytes used (numbers are never
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encoded with 8 bytes). For example:
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Number Encoding
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0 0x00
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0x1f 0xf8 (0 | (0x1f << 3))
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0x20 0x01 0x01
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0xf6 0xb1 0x07
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0xd34a 0x52 0x9a 0x06
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0x1fffffffffffff 0xfe 0xff 0xff 0xff 0xff 0xff 0xff
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0x20000000000000 0x07 0x00 0x00 0x00 0x00 0x00 0x00 0x01 0x00
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0xffffffffffffffff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0xff 0x07
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The main advantage over something like base-128 compression (also called
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varint) is that the encoding and decoding can happen with just a single
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conditional jump to determine if one or two 64-bit words are involved (or
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even no or only well-predicted conditional jump if unaligned reads/writes
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and buffer padding can be assumed).
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*/
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#define COMPR_INT_MAX32 5
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#define COMPR_INT_MAX64 9
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#define COMPR_INT_MAX COMPR_INT_MAX64
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/* Write compressed unsigned integer */
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extern unsigned char *compr_int_write(unsigned char *p, uint64_t v);
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/*
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Read compressed integer.
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Returns a pair of the value read and the incremented pointer.
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*/
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extern std::pair<uint64_t, const unsigned char *>
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compr_int_read(const unsigned char *p);
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#endif /* MY_COMPR_INT_H */
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