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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>
98 lines
3.5 KiB
C++
98 lines
3.5 KiB
C++
#ifndef HANDLER_BINLOG_READER_INCLUDED
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#define HANDLER_BINLOG_READER_INCLUDED
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/* Copyright (c) 2025, Kristian Nielsen.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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class String;
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class THD;
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struct slave_connection_state;
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struct rpl_binlog_state_base;
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/*
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Class for reading a binlog implemented in an engine.
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*/
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class handler_binlog_reader {
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public:
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/*
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Approximate current position (from which next call to read_binlog_data()
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will need to read). Updated by the engine. Used to know which binlog files
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the active dump threads are currently reading from, to avoid purging
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actively used binlogs.
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*/
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uint64_t cur_file_no;
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uint64_t cur_file_pos;
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private:
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/* Position and length of any remaining data in buf[]. */
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uint32_t buf_data_pos;
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uint32_t buf_data_remain;
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/* Buffer used when reading data out via read_binlog_data(). */
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static constexpr size_t BUF_SIZE= 32768;
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uchar *buf;
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public:
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handler_binlog_reader()
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: cur_file_no(~(uint64_t)0), cur_file_pos(~(uint64_t)0),
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buf_data_pos(0), buf_data_remain(0)
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{
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buf= (uchar *)my_malloc(PSI_INSTRUMENT_ME, BUF_SIZE, MYF(0));
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}
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virtual ~handler_binlog_reader() {
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my_free(buf);
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};
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virtual int read_binlog_data(uchar *buf, uint32_t len) = 0;
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virtual bool data_available()= 0;
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/*
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Wait for data to be available to read, for kill, or for timeout.
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Returns true in case of timeout reached, false otherwise.
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Caller should check for kill before calling again (to avoid busy-loop).
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*/
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virtual bool wait_available(THD *thd, const struct timespec *abstime) = 0;
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/*
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This initializes the current read position to the point of the slave GTID
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position passed in as POS. It is permissible to start at a position a bit
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earlier in the binlog, only cost is the extra read cost of reading not
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needed event data.
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If position is found, must return the corresponding binlog state in the
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STATE output parameter and initialize cur_file_no and cur_file_pos members.
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Returns:
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-1 Error
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0 The requested GTID position not found, needed binlogs have been purged
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1 Ok, position found and returned.
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*/
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virtual int init_gtid_pos(THD *thd, slave_connection_state *pos,
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rpl_binlog_state_base *state) = 0;
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/*
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Initialize to a legacy-type position (filename, offset). This mostly to
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support legacy SHOW BINLOG EVENTS.
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*/
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virtual int init_legacy_pos(THD *thd, const char *filename,
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ulonglong offset) = 0;
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/*
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Can be called after init_gtid_pos() or init_legacy_pos() to make the reader
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stop (return EOF) at the end of the binlog file. Used for SHOW BINLOG
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EVENTS, which has a file-based interface based on legacy file name.
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*/
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virtual void enable_single_file() = 0;
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int read_log_event(String *packet, uint32_t ev_offset, size_t max_allowed);
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};
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#endif /* HANDLER_BINLOG_READER_INCLUDED */
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