mirror of
https://github.com/MariaDB/server.git
synced 2025-10-31 19:06:14 +01:00
638c62acac
Starting with GCC 7 and clang 15, single-bit operations such as fetch_or(1) & 1 are translated into 80386 instructions such as LOCK BTS, instead of using the generic translation pattern of emitting a loop around LOCK CMPXCHG. Given that the oldest currently supported GNU/Linux distributions ship GCC 7, and that older versions of GCC are out of support, let us remove some work-arounds that are not strictly necessary. If someone compiles the code using an older compiler, it will work but possibly less efficiently. srw_mutex_impl::HOLDER: Changed from 1U<<31 to 1 in order to work around https://github.com/llvm/llvm-project/issues/37322 which is specific to setting the most significant bit. srw_mutex_impl::WAITER: A multiplier of waiting requests. This used to be 1, which would now collide with HOLDER. fil_space_t::set_stopping(): Remove this unused function. In MSVC we need _interlockedbittestandset() for LOCK BTS.
287 lines
10 KiB
C++
287 lines
10 KiB
C++
/*****************************************************************************
|
|
|
|
Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
|
|
Copyright (c) 2017, 2022, MariaDB Corporation.
|
|
|
|
This program 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; version 2 of the License.
|
|
|
|
This program 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
|
|
this program; if not, write to the Free Software Foundation, Inc.,
|
|
51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA
|
|
|
|
*****************************************************************************/
|
|
|
|
/**************************************************//**
|
|
@file include/trx0rseg.h
|
|
Rollback segment
|
|
|
|
Created 3/26/1996 Heikki Tuuri
|
|
*******************************************************/
|
|
|
|
#pragma once
|
|
#include "trx0types.h"
|
|
#include "fut0lst.h"
|
|
|
|
/** Create a rollback segment header.
|
|
@param[in,out] space system, undo, or temporary tablespace
|
|
@param[in] rseg_id rollback segment identifier
|
|
@param[in] max_trx_id new value of TRX_RSEG_MAX_TRX_ID
|
|
@param[in,out] mtr mini-transaction
|
|
@param[out] err error code
|
|
@return the created rollback segment
|
|
@retval nullptr on failure */
|
|
buf_block_t *trx_rseg_header_create(fil_space_t *space, ulint rseg_id,
|
|
trx_id_t max_trx_id, mtr_t *mtr,
|
|
dberr_t *err)
|
|
MY_ATTRIBUTE((nonnull, warn_unused_result));
|
|
|
|
/** Initialize or recover the rollback segments at startup. */
|
|
dberr_t trx_rseg_array_init();
|
|
|
|
/** Create the temporary rollback segments. */
|
|
dberr_t trx_temp_rseg_create(mtr_t *mtr);
|
|
|
|
/* Number of undo log slots in a rollback segment file copy */
|
|
#define TRX_RSEG_N_SLOTS (srv_page_size / 16)
|
|
|
|
/* Maximum number of transactions supported by a single rollback segment */
|
|
#define TRX_RSEG_MAX_N_TRXS (TRX_RSEG_N_SLOTS / 2)
|
|
|
|
/** The rollback segment memory object */
|
|
struct alignas(CPU_LEVEL1_DCACHE_LINESIZE) trx_rseg_t
|
|
{
|
|
/** tablespace containing the rollback segment; constant after init() */
|
|
fil_space_t *space;
|
|
/** latch protecting everything except page_no, space */
|
|
IF_DBUG(srw_lock_debug,srw_spin_lock) latch;
|
|
/** rollback segment header page number; constant after init() */
|
|
uint32_t page_no;
|
|
/** length of the TRX_RSEG_HISTORY list (number of transactions) */
|
|
uint32_t history_size;
|
|
|
|
/** Last known transaction that has not been purged yet,
|
|
or 0 if everything has been purged. */
|
|
trx_id_t needs_purge;
|
|
|
|
private:
|
|
/** Reference counter to track is_persistent() transactions,
|
|
with SKIP flag. */
|
|
std::atomic<uint32_t> ref;
|
|
public:
|
|
/** Whether undo tablespace truncation is pending */
|
|
static constexpr uint32_t SKIP= 1;
|
|
/** Transaction reference count multiplier */
|
|
static constexpr uint32_t REF= 2;
|
|
|
|
/** @return the reference count and flags */
|
|
uint32_t ref_load() const { return ref.load(std::memory_order_relaxed); }
|
|
private:
|
|
/** Set the SKIP bit */
|
|
void ref_set_skip()
|
|
{
|
|
ref.fetch_or(SKIP, std::memory_order_relaxed);
|
|
}
|
|
/** Clear a bit in ref */
|
|
void ref_reset_skip()
|
|
{
|
|
ref.fetch_and(~SKIP, std::memory_order_relaxed);
|
|
}
|
|
|
|
public:
|
|
|
|
/** Initialize the fields that are not zero-initialized. */
|
|
void init(fil_space_t *space, uint32_t page);
|
|
/** Reinitialize the fields on undo tablespace truncation. */
|
|
void reinit(uint32_t page);
|
|
/** Clean up. */
|
|
void destroy();
|
|
|
|
/** Note that undo tablespace truncation was started. */
|
|
void set_skip_allocation() { ut_ad(is_persistent()); ref_set_skip(); }
|
|
/** Note that undo tablespace truncation was completed. */
|
|
void clear_skip_allocation()
|
|
{
|
|
ut_ad(is_persistent());
|
|
#if defined DBUG_OFF
|
|
ref_reset_skip();
|
|
#else
|
|
ut_d(auto r=) ref.fetch_and(~SKIP, std::memory_order_relaxed);
|
|
ut_ad(r == SKIP);
|
|
#endif
|
|
}
|
|
/** @return whether the segment is marked for undo truncation */
|
|
bool skip_allocation() const
|
|
{ return ref.load(std::memory_order_acquire) & SKIP; }
|
|
/** Increment the reference count */
|
|
void acquire()
|
|
{ ut_d(auto r=) ref.fetch_add(REF); ut_ad(!(r & SKIP)); }
|
|
/** Increment the reference count if possible
|
|
@retval true if the reference count was incremented
|
|
@retval false if skip_allocation() holds */
|
|
bool acquire_if_available()
|
|
{
|
|
uint32_t r= 0;
|
|
while (!ref.compare_exchange_weak(r, r + REF,
|
|
std::memory_order_relaxed,
|
|
std::memory_order_relaxed))
|
|
if (r & SKIP)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/** Decrement the reference count */
|
|
void release()
|
|
{
|
|
ut_d(const auto r=)
|
|
ref.fetch_sub(REF, std::memory_order_relaxed);
|
|
ut_ad(r >= REF);
|
|
}
|
|
/** @return whether references exist */
|
|
bool is_referenced() const { return ref_load() >= REF; }
|
|
|
|
/** current size in pages */
|
|
uint32_t curr_size;
|
|
|
|
/** List of undo logs (transactions) */
|
|
UT_LIST_BASE_NODE_T(trx_undo_t) undo_list;
|
|
/** List of undo log segments cached for fast reuse */
|
|
UT_LIST_BASE_NODE_T(trx_undo_t) undo_cached;
|
|
|
|
/** Last not yet purged undo log header; FIL_NULL if all purged */
|
|
uint32_t last_page_no;
|
|
|
|
/** trx_t::no << 16 | last_offset */
|
|
uint64_t last_commit_and_offset;
|
|
|
|
/** @return the commit ID of the last committed transaction */
|
|
trx_id_t last_trx_no() const
|
|
{ return last_commit_and_offset >> 16; }
|
|
/** @return header offset of the last committed transaction */
|
|
uint16_t last_offset() const
|
|
{
|
|
return static_cast<uint16_t>(last_commit_and_offset);
|
|
}
|
|
|
|
void set_last_commit(uint16_t last_offset, trx_id_t trx_no)
|
|
{
|
|
last_commit_and_offset= trx_no << 16 | static_cast<uint64_t>(last_offset);
|
|
}
|
|
|
|
/** @return the page identifier */
|
|
page_id_t page_id() const { return page_id_t{space->id, page_no}; }
|
|
|
|
/** @return the rollback segment header page, exclusively latched */
|
|
buf_block_t *get(mtr_t *mtr, dberr_t *err) const;
|
|
|
|
/** @return whether the rollback segment is persistent */
|
|
bool is_persistent() const
|
|
{
|
|
ut_ad(space == fil_system.temp_space || space == fil_system.sys_space ||
|
|
(srv_undo_space_id_start > 0 &&
|
|
space->id >= srv_undo_space_id_start &&
|
|
space->id <= srv_undo_space_id_start + TRX_SYS_MAX_UNDO_SPACES));
|
|
ut_ad(space == fil_system.temp_space || space == fil_system.sys_space ||
|
|
!srv_was_started ||
|
|
(srv_undo_space_id_start > 0 &&
|
|
space->id >= srv_undo_space_id_start
|
|
&& space->id <= srv_undo_space_id_start +
|
|
srv_undo_tablespaces_open));
|
|
return space->id != SRV_TMP_SPACE_ID;
|
|
}
|
|
};
|
|
|
|
/* Undo log segment slot in a rollback segment header */
|
|
/*-------------------------------------------------------------*/
|
|
#define TRX_RSEG_SLOT_PAGE_NO 0 /* Page number of the header page of
|
|
an undo log segment */
|
|
/*-------------------------------------------------------------*/
|
|
/* Slot size */
|
|
#define TRX_RSEG_SLOT_SIZE 4
|
|
|
|
/* The offset of the rollback segment header on its page */
|
|
#define TRX_RSEG FSEG_PAGE_DATA
|
|
|
|
/* Transaction rollback segment header */
|
|
/*-------------------------------------------------------------*/
|
|
/** 0xfffffffe = pre-MariaDB 10.3.5 format; 0=MariaDB 10.3.5 or later */
|
|
#define TRX_RSEG_FORMAT 0
|
|
/** Number of pages in the TRX_RSEG_HISTORY list */
|
|
#define TRX_RSEG_HISTORY_SIZE 4
|
|
/** Committed transaction logs that have not been purged yet */
|
|
#define TRX_RSEG_HISTORY 8
|
|
#define TRX_RSEG_FSEG_HEADER (8 + FLST_BASE_NODE_SIZE)
|
|
/* Header for the file segment where
|
|
this page is placed */
|
|
#define TRX_RSEG_UNDO_SLOTS (8 + FLST_BASE_NODE_SIZE + FSEG_HEADER_SIZE)
|
|
/* Undo log segment slots */
|
|
/** Maximum transaction ID (valid only if TRX_RSEG_FORMAT is 0) */
|
|
#define TRX_RSEG_MAX_TRX_ID (TRX_RSEG_UNDO_SLOTS + TRX_RSEG_N_SLOTS \
|
|
* TRX_RSEG_SLOT_SIZE)
|
|
|
|
/** 8 bytes offset within the binlog file */
|
|
#define TRX_RSEG_BINLOG_OFFSET TRX_RSEG_MAX_TRX_ID + 8
|
|
/** MySQL log file name, 512 bytes, including terminating NUL
|
|
(valid only if TRX_RSEG_FORMAT is 0).
|
|
If no binlog information is present, the first byte is NUL. */
|
|
#define TRX_RSEG_BINLOG_NAME TRX_RSEG_MAX_TRX_ID + 16
|
|
/** Maximum length of binlog file name, including terminating NUL, in bytes */
|
|
#define TRX_RSEG_BINLOG_NAME_LEN 512
|
|
|
|
#ifdef WITH_WSREP
|
|
# include "trx0xa.h"
|
|
|
|
/** Update the WSREP XID information in rollback segment header.
|
|
@param[in,out] rseg_header rollback segment header
|
|
@param[in] xid WSREP XID
|
|
@param[in,out] mtr mini-transaction */
|
|
void
|
|
trx_rseg_update_wsrep_checkpoint(
|
|
buf_block_t* rseg_header,
|
|
const XID* xid,
|
|
mtr_t* mtr);
|
|
|
|
/** Update WSREP checkpoint XID in first rollback segment header
|
|
as part of wsrep_set_SE_checkpoint() when it is guaranteed that there
|
|
are no wsrep transactions committing.
|
|
If the UUID part of the WSREP XID does not match to the UUIDs of XIDs already
|
|
stored into rollback segments, the WSREP XID in all the remaining rollback
|
|
segments will be reset.
|
|
@param[in] xid WSREP XID */
|
|
void trx_rseg_update_wsrep_checkpoint(const XID* xid);
|
|
|
|
/** Recover the latest WSREP checkpoint XID.
|
|
@param[out] xid WSREP XID
|
|
@return whether the WSREP XID was found */
|
|
bool trx_rseg_read_wsrep_checkpoint(XID& xid);
|
|
#endif /* WITH_WSREP */
|
|
|
|
/** Read the page number of an undo log slot.
|
|
@param[in] rseg_header rollback segment header
|
|
@param[in] n slot number */
|
|
inline uint32_t trx_rsegf_get_nth_undo(const buf_block_t *rseg_header, ulint n)
|
|
{
|
|
ut_ad(n < TRX_RSEG_N_SLOTS);
|
|
return mach_read_from_4(TRX_RSEG + TRX_RSEG_UNDO_SLOTS +
|
|
n * TRX_RSEG_SLOT_SIZE + rseg_header->page.frame);
|
|
}
|
|
|
|
/** Upgrade a rollback segment header page to MariaDB 10.3 format.
|
|
@param[in,out] rseg_header rollback segment header page
|
|
@param[in,out] mtr mini-transaction */
|
|
void trx_rseg_format_upgrade(buf_block_t *rseg_header, mtr_t *mtr);
|
|
|
|
/** Update the offset information about the end of the binlog entry
|
|
which corresponds to the transaction just being committed.
|
|
In a replication slave, this updates the master binlog position
|
|
up to which replication has proceeded.
|
|
@param[in,out] rseg_header rollback segment header
|
|
@param[in] trx committing transaction
|
|
@param[in,out] mtr mini-transaction */
|
|
void trx_rseg_update_binlog_offset(buf_block_t *rseg_header, const trx_t *trx,
|
|
mtr_t *mtr);
|