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mariadb/storage/innobase/trx/trx0undo.cc
Marko Mäkelä b1ab211dee MDEV-15053 Reduce buf_pool_t::mutex contention 
User-visible changes: The INFORMATION_SCHEMA views INNODB_BUFFER_PAGE
and INNODB_BUFFER_PAGE_LRU will report a dummy value FLUSH_TYPE=0
and will no longer report the PAGE_STATE value READY_FOR_USE.

We will remove some fields from buf_page_t and move much code to
member functions of buf_pool_t and buf_page_t, so that the access
rules of data members can be enforced consistently.

Evicting or adding pages in buf_pool.LRU will remain covered by
buf_pool.mutex.

Evicting or adding pages in buf_pool.page_hash will remain
covered by both buf_pool.mutex and the buf_pool.page_hash X-latch.

After this fix, buf_pool.page_hash lookups can entirely
avoid acquiring buf_pool.mutex, only relying on
buf_pool.hash_lock_get() S-latch.

Similarly, buf_flush_check_neighbors() can will rely solely on
buf_pool.mutex, no buf_pool.page_hash latch at all.

The buf_pool.mutex is rather contended in I/O heavy benchmarks,
especially when the workload does not fit in the buffer pool.

The first attempt to alleviate the contention was the
buf_pool_t::mutex split in
commit 4ed7082eef
which introduced buf_block_t::mutex, which we are now removing.

Later, multiple instances of buf_pool_t were introduced
in commit c18084f71b
and recently removed by us in
commit 1a6f708ec5 (MDEV-15058).

UNIV_BUF_DEBUG: Remove. This option to enable some buffer pool
related debugging in otherwise non-debug builds has not been used
for years. Instead, we have been using UNIV_DEBUG, which is enabled
in CMAKE_BUILD_TYPE=Debug.

buf_block_t::mutex, buf_pool_t::zip_mutex: Remove. We can mainly rely on
std::atomic and the buf_pool.page_hash latches, and in some cases
depend on buf_pool.mutex or buf_pool.flush_list_mutex just like before.
We must always release buf_block_t::lock before invoking
unfix() or io_unfix(), to prevent a glitch where a block that was
added to the buf_pool.free list would apper X-latched. See
commit c5883debd6 how this glitch
was finally caught in a debug environment.

We move some buf_pool_t::page_hash specific code from the
ha and hash modules to buf_pool, for improved readability.

buf_pool_t::close(): Assert that all blocks are clean, except
on aborted startup or crash-like shutdown.

buf_pool_t::validate(): No longer attempt to validate
n_flush[] against the number of BUF_IO_WRITE fixed blocks,
because buf_page_t::flush_type no longer exists.

buf_pool_t::watch_set(): Replaces buf_pool_watch_set().
Reduce mutex contention by separating the buf_pool.watch[]
allocation and the insert into buf_pool.page_hash.

buf_pool_t::page_hash_lock<bool exclusive>(): Acquire a
buf_pool.page_hash latch.
Replaces and extends buf_page_hash_lock_s_confirm()
and buf_page_hash_lock_x_confirm().

buf_pool_t::READ_AHEAD_PAGES: Renamed from BUF_READ_AHEAD_PAGES.

buf_pool_t::curr_size, old_size, read_ahead_area, n_pend_reads:
Use Atomic_counter.

buf_pool_t::running_out(): Replaces buf_LRU_buf_pool_running_out().

buf_pool_t::LRU_remove(): Remove a block from the LRU list
and return its predecessor. Incorporates buf_LRU_adjust_hp(),
which was removed.

buf_page_get_gen(): Remove a redundant call of fsp_is_system_temporary(),
for mode == BUF_GET_IF_IN_POOL_OR_WATCH, which is only used by
BTR_DELETE_OP (purge), which is never invoked on temporary tables.

buf_free_from_unzip_LRU_list_batch(): Avoid redundant assignments.

buf_LRU_free_from_unzip_LRU_list(): Simplify the loop condition.

buf_LRU_free_page(): Clarify the function comment.

buf_flush_check_neighbor(), buf_flush_check_neighbors():
Rewrite the construction of the page hash range. We will hold
the buf_pool.mutex for up to buf_pool.read_ahead_area (at most 64)
consecutive lookups of buf_pool.page_hash.

buf_flush_page_and_try_neighbors(): Remove.
Merge to its only callers, and remove redundant operations in
buf_flush_LRU_list_batch().

buf_read_ahead_random(), buf_read_ahead_linear(): Rewrite.
Do not acquire buf_pool.mutex, and iterate directly with page_id_t.

ut_2_power_up(): Remove. my_round_up_to_next_power() is inlined
and avoids any loops.

fil_page_get_prev(), fil_page_get_next(), fil_addr_is_null(): Remove.

buf_flush_page(): Add a fil_space_t* parameter. Minimize the
buf_pool.mutex hold time. buf_pool.n_flush[] is no longer updated
atomically with the io_fix, and we will protect most buf_block_t
fields with buf_block_t::lock. The function
buf_flush_write_block_low() is removed and merged here.

buf_page_init_for_read(): Use static linkage. Initialize the newly
allocated block and acquire the exclusive buf_block_t::lock while not
holding any mutex.

IORequest::IORequest(): Remove the body. We only need to invoke
set_punch_hole() in buf_flush_page() and nowhere else.

buf_page_t::flush_type: Remove. Replaced by IORequest::flush_type.
This field is only used during a fil_io() call.
That function already takes IORequest as a parameter, so we had
better introduce  for the rarely changing field.

buf_block_t::init(): Replaces buf_page_init().

buf_page_t::init(): Replaces buf_page_init_low().

buf_block_t::initialise(): Initialise many fields, but
keep the buf_page_t::state(). Both buf_pool_t::validate() and
buf_page_optimistic_get() requires that buf_page_t::in_file()
be protected atomically with buf_page_t::in_page_hash
and buf_page_t::in_LRU_list.

buf_page_optimistic_get(): Now that buf_block_t::mutex
no longer exists, we must check buf_page_t::io_fix()
after acquiring the buf_pool.page_hash lock, to detect
whether buf_page_init_for_read() has been initiated.
We will also check the io_fix() before acquiring hash_lock
in order to avoid unnecessary computation.
The field buf_block_t::modify_clock (protected by buf_block_t::lock)
allows buf_page_optimistic_get() to validate the block.

buf_page_t::real_size: Remove. It was only used while flushing
pages of page_compressed tables.

buf_page_encrypt(): Add an output parameter that allows us ot eliminate
buf_page_t::real_size. Replace a condition with debug assertion.

buf_page_should_punch_hole(): Remove.

buf_dblwr_t::add_to_batch(): Replaces buf_dblwr_add_to_batch().
Add the parameter size (to replace buf_page_t::real_size).

buf_dblwr_t::write_single_page(): Replaces buf_dblwr_write_single_page().
Add the parameter size (to replace buf_page_t::real_size).

fil_system_t::detach(): Replaces fil_space_detach().
Ensure that fil_validate() will not be violated even if
fil_system.mutex is released and reacquired.

fil_node_t::complete_io(): Renamed from fil_node_complete_io().

fil_node_t::close_to_free(): Replaces fil_node_close_to_free().
Avoid invoking fil_node_t::close() because fil_system.n_open
has already been decremented in fil_space_t::detach().

BUF_BLOCK_READY_FOR_USE: Remove. Directly use BUF_BLOCK_MEMORY.

BUF_BLOCK_ZIP_DIRTY: Remove. Directly use BUF_BLOCK_ZIP_PAGE,
and distinguish dirty pages by buf_page_t::oldest_modification().

BUF_BLOCK_POOL_WATCH: Remove. Use BUF_BLOCK_NOT_USED instead.
This state was only being used for buf_page_t that are in
buf_pool.watch.

buf_pool_t::watch[]: Remove pointer indirection.

buf_page_t::in_flush_list: Remove. It was set if and only if
buf_page_t::oldest_modification() is nonzero.

buf_page_decrypt_after_read(), buf_corrupt_page_release(),
buf_page_check_corrupt(): Change the const fil_space_t* parameter
to const fil_node_t& so that we can report the correct file name.

buf_page_monitor(): Declare as an ATTRIBUTE_COLD global function.

buf_page_io_complete(): Split to buf_page_read_complete() and
buf_page_write_complete().

buf_dblwr_t::in_use: Remove.

buf_dblwr_t::buf_block_array: Add IORequest::flush_t.

buf_dblwr_sync_datafiles(): Remove. It was a useless wrapper of
os_aio_wait_until_no_pending_writes().

buf_flush_write_complete(): Declare static, not global.
Add the parameter IORequest::flush_t.

buf_flush_freed_page(): Simplify the code.

recv_sys_t::flush_lru: Renamed from flush_type and changed to bool.

fil_read(), fil_write(): Replaced with direct use of fil_io().

fil_buffering_disabled(): Remove. Check srv_file_flush_method directly.

fil_mutex_enter_and_prepare_for_io(): Return the resolved
fil_space_t* to avoid a duplicated lookup in the caller.

fil_report_invalid_page_access(): Clean up the parameters.

fil_io(): Return fil_io_t, which comprises fil_node_t and error code.
Always invoke fil_space_t::acquire_for_io() and let either the
sync=true caller or fil_aio_callback() invoke
fil_space_t::release_for_io().

fil_aio_callback(): Rewrite to replace buf_page_io_complete().

fil_check_pending_operations(): Remove a parameter, and remove some
redundant lookups.

fil_node_close_to_free(): Wait for n_pending==0. Because we no longer
do an extra lookup of the tablespace between fil_io() and the
completion of the operation, we must give fil_node_t::complete_io() a
chance to decrement the counter.

fil_close_tablespace(): Remove unused parameter trx, and document
that this is only invoked during the error handling of IMPORT TABLESPACE.

row_import_discard_changes(): Merged with the only caller,
row_import_cleanup(). Do not lock up the data dictionary while
invoking fil_close_tablespace().

logs_empty_and_mark_files_at_shutdown(): Do not invoke
fil_close_all_files(), to avoid a !needs_flush assertion failure
on fil_node_t::close().

innodb_shutdown(): Invoke os_aio_free() before fil_close_all_files().

fil_close_all_files(): Invoke fil_flush_file_spaces()
to ensure proper durability.

thread_pool::unbind(): Fix a crash that would occur on Windows
after srv_thread_pool->disable_aio() and os_file_close().
This fix was submitted by Vladislav Vaintroub.

Thanks to Matthias Leich and Axel Schwenke for extensive testing,
Vladislav Vaintroub for helpful comments, and Eugene Kosov for a review.
2020-06-05 12:35:46 +03:00

1413 lines
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/*****************************************************************************
Copyright (c) 1996, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2014, 2020, 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 trx/trx0undo.cc
Transaction undo log
Created 3/26/1996 Heikki Tuuri
*******************************************************/
#include "trx0undo.h"
#include "fsp0fsp.h"
#include "mach0data.h"
#include "mtr0log.h"
#include "srv0mon.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "trx0purge.h"
#include "trx0rec.h"
#include "trx0rseg.h"
/* How should the old versions in the history list be managed?
----------------------------------------------------------
If each transaction is given a whole page for its update undo log, file
space consumption can be 10 times higher than necessary. Therefore,
partly filled update undo log pages should be reusable. But then there
is no way individual pages can be ordered so that the ordering agrees
with the serialization numbers of the transactions on the pages. Thus,
the history list must be formed of undo logs, not their header pages as
it was in the old implementation.
However, on a single header page the transactions are placed in
the order of their serialization numbers. As old versions are purged, we
may free the page when the last transaction on the page has been purged.
A problem is that the purge has to go through the transactions
in the serialization order. This means that we have to look through all
rollback segments for the one that has the smallest transaction number
in its history list.
When should we do a purge? A purge is necessary when space is
running out in any of the rollback segments. Then we may have to purge
also old version which might be needed by some consistent read. How do
we trigger the start of a purge? When a transaction writes to an undo log,
it may notice that the space is running out. When a read view is closed,
it may make some history superfluous. The server can have an utility which
periodically checks if it can purge some history.
In a parallellized purge we have the problem that a query thread
can remove a delete marked clustered index record before another query
thread has processed an earlier version of the record, which cannot then
be done because the row cannot be constructed from the clustered index
record. To avoid this problem, we will store in the update and delete mark
undo record also the columns necessary to construct the secondary index
entries which are modified.
We can latch the stack of versions of a single clustered index record
by taking a latch on the clustered index page. As long as the latch is held,
no new versions can be added and no versions removed by undo. But, a purge
can still remove old versions from the bottom of the stack. */
/* How to protect rollback segments, undo logs, and history lists with
-------------------------------------------------------------------
latches?
-------
When a transaction does its first insert or modify in the clustered index, an
undo log is assigned for it. Then we must have an x-latch to the rollback
segment header.
When the transaction performs modifications or rolls back, its
undo log is protected by undo page latches.
Only the thread that is associated with the transaction may hold multiple
undo page latches at a time. Undo pages are always private to a single
transaction. Other threads that are performing MVCC reads
or checking for implicit locks will lock at most one undo page at a time
in trx_undo_get_undo_rec_low().
When the transaction commits, its persistent undo log is added
to the history list. If it is not suitable for reuse, its slot is reset.
In both cases, an x-latch must be acquired on the rollback segment header page.
The purge operation steps through the history list without modifying
it until a truncate operation occurs, which can remove undo logs from the end
of the list and release undo log segments. In stepping through the list,
s-latches on the undo log pages are enough, but in a truncate, x-latches must
be obtained on the rollback segment and individual pages. */
/********************************************************************//**
Creates and initializes an undo log memory object.
@return own: the undo log memory object */
static
trx_undo_t*
trx_undo_mem_create(
/*================*/
trx_rseg_t* rseg, /*!< in: rollback segment memory object */
ulint id, /*!< in: slot index within rseg */
trx_id_t trx_id, /*!< in: id of the trx for which the undo log
is created */
const XID* xid, /*!< in: X/Open XA transaction identification*/
uint32_t page_no,/*!< in: undo log header page number */
uint16_t offset);/*!< in: undo log header byte offset on page */
/** Determine the start offset of undo log records of an undo log page.
@param[in] block undo log page
@param[in] page_no undo log header page number
@param[in] offset undo log header offset
@return start offset */
static
uint16_t trx_undo_page_get_start(const buf_block_t *block, uint32_t page_no,
uint16_t offset)
{
return page_no == block->page.id().page_no()
? mach_read_from_2(offset + TRX_UNDO_LOG_START + block->frame)
: TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE;
}
/** Get the first undo log record on a page.
@param[in] block undo log page
@param[in] page_no undo log header page number
@param[in] offset undo log header page offset
@return pointer to first record
@retval NULL if none exists */
static trx_undo_rec_t*
trx_undo_page_get_first_rec(const buf_block_t *block, uint32_t page_no,
uint16_t offset)
{
uint16_t start= trx_undo_page_get_start(block, page_no, offset);
return start == trx_undo_page_get_end(block, page_no, offset)
? nullptr : block->frame + start;
}
/** Get the last undo log record on a page.
@param[in] page undo log page
@param[in] page_no undo log header page number
@param[in] offset undo log header page offset
@return pointer to last record
@retval NULL if none exists */
static
trx_undo_rec_t*
trx_undo_page_get_last_rec(const buf_block_t *block, uint32_t page_no,
uint16_t offset)
{
uint16_t end= trx_undo_page_get_end(block, page_no, offset);
return trx_undo_page_get_start(block, page_no, offset) == end
? nullptr : block->frame + mach_read_from_2(block->frame + end - 2);
}
/** Get the previous record in an undo log from the previous page.
@param[in,out] block undo log page
@param[in] rec undo record offset in the page
@param[in] page_no undo log header page number
@param[in] offset undo log header offset on page
@param[in] shared latching mode: true=RW_S_LATCH, false=RW_X_LATCH
@param[in,out] mtr mini-transaction
@return undo log record, the page latched, NULL if none */
static trx_undo_rec_t*
trx_undo_get_prev_rec_from_prev_page(buf_block_t *&block, uint16_t rec,
uint32_t page_no, uint16_t offset,
bool shared, mtr_t *mtr)
{
uint32_t prev_page_no= flst_get_prev_addr(TRX_UNDO_PAGE_HDR +
TRX_UNDO_PAGE_NODE +
block->frame).page;
if (prev_page_no == FIL_NULL)
return nullptr;
block= buf_page_get(page_id_t(block->page.id().space(), prev_page_no),
0, shared ? RW_S_LATCH : RW_X_LATCH, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
return trx_undo_page_get_last_rec(block, page_no, offset);
}
/** Get the previous undo log record.
@param[in] block undo log page
@param[in] rec undo log record
@param[in] page_no undo log header page number
@param[in] offset undo log header page offset
@return pointer to record
@retval NULL if none */
static
trx_undo_rec_t*
trx_undo_page_get_prev_rec(const buf_block_t *block, trx_undo_rec_t *rec,
uint32_t page_no, uint16_t offset)
{
ut_ad(block->frame == page_align(rec));
return rec == block->frame + trx_undo_page_get_start(block, page_no, offset)
? nullptr
: block->frame + mach_read_from_2(rec - 2);
}
/** Get the previous record in an undo log.
@param[in,out] block undo log page
@param[in] rec undo record offset in the page
@param[in] page_no undo log header page number
@param[in] offset undo log header offset on page
@param[in] shared latching mode: true=RW_S_LATCH, false=RW_X_LATCH
@param[in,out] mtr mini-transaction
@return undo log record, the page latched, NULL if none */
trx_undo_rec_t*
trx_undo_get_prev_rec(buf_block_t *&block, uint16_t rec, uint32_t page_no,
uint16_t offset, bool shared, mtr_t *mtr)
{
if (trx_undo_rec_t *prev= trx_undo_page_get_prev_rec(block,
block->frame + rec,
page_no, offset))
return prev;
/* We have to go to the previous undo log page to look for the
previous record */
return trx_undo_get_prev_rec_from_prev_page(block, rec, page_no, offset,
shared, mtr);
}
/** Get the next record in an undo log from the next page.
@param[in,out] block undo log page
@param[in] page_no undo log header page number
@param[in] offset undo log header offset on page
@param[in] mode latching mode: RW_S_LATCH or RW_X_LATCH
@param[in,out] mtr mini-transaction
@return undo log record, the page latched, NULL if none */
static trx_undo_rec_t*
trx_undo_get_next_rec_from_next_page(buf_block_t *&block, uint32_t page_no,
uint16_t offset, ulint mode, mtr_t *mtr)
{
if (page_no == block->page.id().page_no() &&
mach_read_from_2(block->frame + offset + TRX_UNDO_NEXT_LOG))
return NULL;
ulint next= flst_get_next_addr(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE +
block->frame).page;
if (next == FIL_NULL)
return NULL;
block= buf_page_get(page_id_t(block->page.id().space(), next), 0, mode, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
return trx_undo_page_get_first_rec(block, page_no, offset);
}
/** Get the next record in an undo log.
@param[in,out] block undo log page
@param[in] rec undo record offset in the page
@param[in] page_no undo log header page number
@param[in] offset undo log header offset on page
@param[in,out] mtr mini-transaction
@return undo log record, the page latched, NULL if none */
trx_undo_rec_t*
trx_undo_get_next_rec(buf_block_t *&block, uint16_t rec, uint32_t page_no,
uint16_t offset, mtr_t *mtr)
{
if (trx_undo_rec_t *next= trx_undo_page_get_next_rec(block, rec, page_no,
offset))
return next;
return trx_undo_get_next_rec_from_next_page(block, page_no, offset,
RW_S_LATCH, mtr);
}
/** Get the first record in an undo log.
@param[in] space undo log header space
@param[in] page_no undo log header page number
@param[in] offset undo log header offset on page
@param[in] mode latching mode: RW_S_LATCH or RW_X_LATCH
@param[out] block undo log page
@param[in,out] mtr mini-transaction
@return undo log record, the page latched, NULL if none */
trx_undo_rec_t*
trx_undo_get_first_rec(const fil_space_t &space, uint32_t page_no,
uint16_t offset, ulint mode, buf_block_t*& block,
mtr_t *mtr)
{
block = buf_page_get(page_id_t(space.id, page_no), 0, mode, mtr);
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
if (trx_undo_rec_t *rec= trx_undo_page_get_first_rec(block, page_no, offset))
return rec;
return trx_undo_get_next_rec_from_next_page(block, page_no, offset, mode,
mtr);
}
/*============== UNDO LOG FILE COPY CREATION AND FREEING ==================*/
/** Initialize an undo log page.
NOTE: This corresponds to a redo log record and must not be changed!
@see mtr_t::undo_create()
@param[in,out] block undo log page */
void trx_undo_page_init(const buf_block_t &block)
{
mach_write_to_2(my_assume_aligned<2>(FIL_PAGE_TYPE + block.frame),
FIL_PAGE_UNDO_LOG);
static_assert(TRX_UNDO_PAGE_HDR == FIL_PAGE_DATA, "compatibility");
memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE + block.frame,
0, 2);
mach_write_to_2(my_assume_aligned<2>
(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START + block.frame),
TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_HDR_SIZE);
memcpy_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE + block.frame,
TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START + block.frame, 2);
/* The following corresponds to flst_zero_both(), but without writing log. */
memset_aligned<4>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_PREV +
FIL_ADDR_PAGE + block.frame, 0xff, 4);
memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_PREV +
FIL_ADDR_BYTE + block.frame, 0, 2);
memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_NEXT +
FIL_ADDR_PAGE + block.frame, 0xff, 4);
memset_aligned<2>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE + FLST_NEXT +
FIL_ADDR_BYTE + block.frame, 0, 2);
static_assert(TRX_UNDO_PAGE_NODE + FLST_NEXT + FIL_ADDR_BYTE + 2 ==
TRX_UNDO_PAGE_HDR_SIZE, "compatibility");
/* Preserve TRX_UNDO_SEG_HDR, but clear the rest of the page. */
memset_aligned<2>(TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE + block.frame, 0,
srv_page_size - (TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE +
FIL_PAGE_DATA_END));
}
/** Look for a free slot for an undo log segment.
@param rseg_header rollback segment header
@return slot index
@retval ULINT_UNDEFINED if not found */
static ulint trx_rsegf_undo_find_free(const buf_block_t *rseg_header)
{
ulint max_slots= TRX_RSEG_N_SLOTS;
#ifdef UNIV_DEBUG
if (trx_rseg_n_slots_debug)
max_slots= std::min<ulint>(trx_rseg_n_slots_debug, TRX_RSEG_N_SLOTS);
#endif
for (ulint i= 0; i < max_slots; i++)
if (trx_rsegf_get_nth_undo(rseg_header, i) == FIL_NULL)
return i;
return ULINT_UNDEFINED;
}
/** Create an undo log segment.
@param[in,out] space tablespace
@param[in,out] rseg_hdr rollback segment header (x-latched)
@param[out] id undo slot number
@param[out] err error code
@param[in,out] mtr mini-transaction
@return undo log block
@retval NULL on failure */
static MY_ATTRIBUTE((nonnull, warn_unused_result))
buf_block_t*
trx_undo_seg_create(fil_space_t *space, buf_block_t *rseg_hdr, ulint *id,
dberr_t *err, mtr_t *mtr)
{
buf_block_t* block;
ulint n_reserved;
bool success;
const ulint slot_no = trx_rsegf_undo_find_free(rseg_hdr);
if (slot_no == ULINT_UNDEFINED) {
ib::warn() << "Cannot find a free slot for an undo log. Do"
" you have too many active transactions running"
" concurrently?";
*err = DB_TOO_MANY_CONCURRENT_TRXS;
return NULL;
}
ut_ad(slot_no < TRX_RSEG_N_SLOTS);
success = fsp_reserve_free_extents(&n_reserved, space, 2, FSP_UNDO,
mtr);
if (!success) {
*err = DB_OUT_OF_FILE_SPACE;
return NULL;
}
/* Allocate a new file segment for the undo log */
block = fseg_create(space, 0, TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER,
mtr, true);
space->release_free_extents(n_reserved);
if (block == NULL) {
*err = DB_OUT_OF_FILE_SPACE;
return NULL;
}
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
mtr->undo_create(*block);
trx_undo_page_init(*block);
mtr->write<2>(*block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE
+ block->frame,
TRX_UNDO_SEG_HDR + TRX_UNDO_SEG_HDR_SIZE);
mtr->write<2,mtr_t::MAYBE_NOP>(*block,
TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG
+ block->frame, 0U);
flst_init(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + block->frame,
mtr);
flst_add_last(block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST,
block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, mtr);
*id = slot_no;
mtr->write<4>(*rseg_hdr, TRX_RSEG + TRX_RSEG_UNDO_SLOTS
+ slot_no * TRX_RSEG_SLOT_SIZE + rseg_hdr->frame,
block->page.id().page_no());
MONITOR_INC(MONITOR_NUM_UNDO_SLOT_USED);
*err = DB_SUCCESS;
return block;
}
/** Initialize an undo log header.
@param[in,out] undo_page undo log segment header page
@param[in] trx_id transaction identifier
@param[in,out] mtr mini-transaction
@return header byte offset on page */
static uint16_t trx_undo_header_create(buf_block_t *undo_page, trx_id_t trx_id,
mtr_t* mtr)
{
/* Reset the TRX_UNDO_PAGE_TYPE in case this page is being
repurposed after upgrading to MariaDB 10.3. */
byte *undo_type= my_assume_aligned<2>
(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE + undo_page->frame);
ut_ad(mach_read_from_2(undo_type) <= TRX_UNDO_UPDATE);
mtr->write<2,mtr_t::MAYBE_NOP>(*undo_page, undo_type, 0U);
byte *start= my_assume_aligned<4>(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START +
undo_page->frame);
const uint16_t free= mach_read_from_2(start + 2);
static_assert(TRX_UNDO_PAGE_START + 2 == TRX_UNDO_PAGE_FREE,
"compatibility");
ut_a(free + TRX_UNDO_LOG_XA_HDR_SIZE < srv_page_size - 100);
mach_write_to_2(start, free + TRX_UNDO_LOG_XA_HDR_SIZE);
/* A WRITE of 2 bytes is never longer than a MEMMOVE.
So, WRITE 2+2 bytes is better than WRITE+MEMMOVE.
But, a MEMSET will only be 1+2 bytes, that is, 1 byte shorter! */
memcpy_aligned<2>(start + 2, start, 2);
mtr->memset(*undo_page, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_START, 4,
start, 2);
uint16_t prev_log= mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG +
undo_page->frame);
alignas(4) byte buf[4];
mach_write_to_2(buf, TRX_UNDO_ACTIVE);
mach_write_to_2(buf + 2, free);
static_assert(TRX_UNDO_STATE + 2 == TRX_UNDO_LAST_LOG, "compatibility");
static_assert(!((TRX_UNDO_SEG_HDR + TRX_UNDO_STATE) % 4), "alignment");
mtr->memcpy(*undo_page, my_assume_aligned<4>
(TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + undo_page->frame),
buf, 4);
if (prev_log)
mtr->write<2>(*undo_page, prev_log + TRX_UNDO_NEXT_LOG + undo_page->frame,
free);
mtr->write<8>(*undo_page, free + TRX_UNDO_TRX_ID + undo_page->frame, trx_id);
/* Write TRX_UNDO_NEEDS_PURGE=1 and TRX_UNDO_LOG_START. */
mach_write_to_2(buf, 1);
memcpy_aligned<2>(buf + 2, start, 2);
static_assert(TRX_UNDO_NEEDS_PURGE + 2 == TRX_UNDO_LOG_START,
"compatibility");
mtr->memcpy<mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_NEEDS_PURGE +
undo_page->frame, buf, 4);
/* Initialize all fields TRX_UNDO_XID_EXISTS to TRX_UNDO_HISTORY_NODE. */
if (prev_log)
{
mtr->memset(undo_page, free + TRX_UNDO_XID_EXISTS,
TRX_UNDO_PREV_LOG - TRX_UNDO_XID_EXISTS, 0);
mtr->write<2,mtr_t::MAYBE_NOP>(*undo_page, free + TRX_UNDO_PREV_LOG +
undo_page->frame, prev_log);
static_assert(TRX_UNDO_PREV_LOG + 2 == TRX_UNDO_HISTORY_NODE,
"compatibility");
mtr->memset(undo_page, free + TRX_UNDO_HISTORY_NODE, FLST_NODE_SIZE, 0);
static_assert(TRX_UNDO_LOG_OLD_HDR_SIZE == TRX_UNDO_HISTORY_NODE +
FLST_NODE_SIZE, "compatibility");
}
else
mtr->memset(undo_page, free + TRX_UNDO_XID_EXISTS,
TRX_UNDO_LOG_OLD_HDR_SIZE - TRX_UNDO_XID_EXISTS, 0);
return free;
}
/** Write X/Open XA Transaction Identifier (XID) to undo log header
@param[in,out] block undo header page
@param[in] offset undo header record offset
@param[in] xid distributed transaction identifier
@param[in,out] mtr mini-transaction */
static void trx_undo_write_xid(buf_block_t *block, uint16_t offset,
const XID &xid, mtr_t *mtr)
{
DBUG_ASSERT(xid.gtrid_length > 0);
DBUG_ASSERT(xid.bqual_length >= 0);
DBUG_ASSERT(xid.gtrid_length <= MAXGTRIDSIZE);
DBUG_ASSERT(xid.bqual_length <= MAXBQUALSIZE);
static_assert(MAXGTRIDSIZE + MAXBQUALSIZE == XIDDATASIZE,
"gtrid and bqual don't fit xid data");
DBUG_ASSERT(mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG +
block->frame) == offset);
trx_ulogf_t* log_hdr= block->frame + offset;
mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_FORMAT,
static_cast<uint32_t>(xid.formatID));
mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_TRID_LEN,
static_cast<uint32_t>(xid.gtrid_length));
mtr->write<4,mtr_t::MAYBE_NOP>(*block, log_hdr + TRX_UNDO_XA_BQUAL_LEN,
static_cast<uint32_t>(xid.bqual_length));
const ulint xid_length= static_cast<ulint>(xid.gtrid_length
+ xid.bqual_length);
mtr->memcpy(*block, &block->frame[offset + TRX_UNDO_XA_XID],
xid.data, xid_length);
if (UNIV_LIKELY(xid_length < XIDDATASIZE))
mtr->memset(block, offset + TRX_UNDO_XA_XID + xid_length,
XIDDATASIZE - xid_length, 0);
}
/********************************************************************//**
Read X/Open XA Transaction Identification (XID) from undo log header */
static
void
trx_undo_read_xid(const trx_ulogf_t* log_hdr, XID* xid)
{
xid->formatID=static_cast<long>(mach_read_from_4(
log_hdr + TRX_UNDO_XA_FORMAT));
xid->gtrid_length=static_cast<long>(mach_read_from_4(
log_hdr + TRX_UNDO_XA_TRID_LEN));
xid->bqual_length=static_cast<long>(mach_read_from_4(
log_hdr + TRX_UNDO_XA_BQUAL_LEN));
memcpy(xid->data, log_hdr + TRX_UNDO_XA_XID, XIDDATASIZE);
}
/** Allocate an undo log page.
@param[in,out] undo undo log
@param[in,out] mtr mini-transaction that does not hold any page latch
@return X-latched block if success
@retval NULL on failure */
buf_block_t* trx_undo_add_page(trx_undo_t* undo, mtr_t* mtr)
{
trx_rseg_t* rseg = undo->rseg;
buf_block_t* new_block = NULL;
ulint n_reserved;
/* When we add a page to an undo log, this is analogous to
a pessimistic insert in a B-tree, and we must reserve the
counterpart of the tree latch, which is the rseg mutex. */
mutex_enter(&rseg->mutex);
buf_block_t* header_block = trx_undo_page_get(
page_id_t(undo->rseg->space->id, undo->hdr_page_no), mtr);
if (!fsp_reserve_free_extents(&n_reserved, undo->rseg->space, 1,
FSP_UNDO, mtr)) {
goto func_exit;
}
new_block = fseg_alloc_free_page_general(
TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER
+ header_block->frame,
undo->top_page_no + 1, FSP_UP, true, mtr, mtr);
rseg->space->release_free_extents(n_reserved);
if (!new_block) {
goto func_exit;
}
ut_ad(rw_lock_get_x_lock_count(&new_block->lock) == 1);
buf_block_dbg_add_level(new_block, SYNC_TRX_UNDO_PAGE);
undo->last_page_no = new_block->page.id().page_no();
mtr->undo_create(*new_block);
trx_undo_page_init(*new_block);
flst_add_last(header_block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST,
new_block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, mtr);
undo->size++;
rseg->curr_size++;
func_exit:
mutex_exit(&rseg->mutex);
return(new_block);
}
/********************************************************************//**
Frees an undo log page that is not the header page.
@return last page number in remaining log */
static
uint32_t
trx_undo_free_page(
/*===============*/
trx_rseg_t* rseg, /*!< in: rollback segment */
bool in_history, /*!< in: TRUE if the undo log is in the history
list */
uint32_t hdr_page_no, /*!< in: header page number */
uint32_t page_no, /*!< in: page number to free: must not be the
header page */
mtr_t* mtr) /*!< in: mtr which does not have a latch to any
undo log page; the caller must have reserved
the rollback segment mutex */
{
const ulint space = rseg->space->id;
ut_a(hdr_page_no != page_no);
ut_ad(mutex_own(&(rseg->mutex)));
buf_block_t* undo_block = trx_undo_page_get(page_id_t(space, page_no),
mtr);
buf_block_t* header_block = trx_undo_page_get(page_id_t(space,
hdr_page_no),
mtr);
flst_remove(header_block, TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST,
undo_block, TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_NODE, mtr);
fseg_free_page(TRX_UNDO_SEG_HDR + TRX_UNDO_FSEG_HEADER
+ header_block->frame,
rseg->space, page_no, mtr);
buf_page_free(page_id_t(space, page_no), mtr, __FILE__, __LINE__);
const fil_addr_t last_addr = flst_get_last(
TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + header_block->frame);
rseg->curr_size--;
if (in_history) {
buf_block_t* rseg_header = trx_rsegf_get(
rseg->space, rseg->page_no, mtr);
byte* rseg_hist_size = TRX_RSEG + TRX_RSEG_HISTORY_SIZE
+ rseg_header->frame;
uint32_t hist_size = mach_read_from_4(rseg_hist_size);
ut_ad(hist_size > 0);
mtr->write<4>(*rseg_header, rseg_hist_size, hist_size - 1);
}
return(last_addr.page);
}
/** Free the last undo log page. The caller must hold the rseg mutex.
@param[in,out] undo undo log
@param[in,out] mtr mini-transaction that does not hold any undo log page
or that has allocated the undo log page */
void
trx_undo_free_last_page(trx_undo_t* undo, mtr_t* mtr)
{
ut_ad(undo->hdr_page_no != undo->last_page_no);
ut_ad(undo->size > 0);
undo->last_page_no = trx_undo_free_page(
undo->rseg, false, undo->hdr_page_no, undo->last_page_no, mtr);
undo->size--;
}
/** Truncate the tail of an undo log during rollback.
@param[in,out] undo undo log
@param[in] limit all undo logs after this limit will be discarded
@param[in] is_temp whether this is temporary undo log */
void trx_undo_truncate_end(trx_undo_t& undo, undo_no_t limit, bool is_temp)
{
mtr_t mtr;
ut_ad(is_temp == !undo.rseg->is_persistent());
for (;;) {
mtr.start();
if (is_temp) {
mtr.set_log_mode(MTR_LOG_NO_REDO);
}
trx_undo_rec_t* trunc_here = NULL;
mutex_enter(&undo.rseg->mutex);
buf_block_t* undo_block = trx_undo_page_get(
page_id_t(undo.rseg->space->id, undo.last_page_no),
&mtr);
trx_undo_rec_t* rec = trx_undo_page_get_last_rec(
undo_block, undo.hdr_page_no, undo.hdr_offset);
while (rec) {
if (trx_undo_rec_get_undo_no(rec) < limit) {
goto func_exit;
}
/* Truncate at least this record off, maybe more */
trunc_here = rec;
rec = trx_undo_page_get_prev_rec(undo_block, rec,
undo.hdr_page_no,
undo.hdr_offset);
}
if (undo.last_page_no != undo.hdr_page_no) {
trx_undo_free_last_page(&undo, &mtr);
mutex_exit(&undo.rseg->mutex);
mtr.commit();
continue;
}
func_exit:
mutex_exit(&undo.rseg->mutex);
if (trunc_here) {
mtr.write<2>(*undo_block,
TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE
+ undo_block->frame,
ulint(trunc_here - undo_block->frame));
}
mtr.commit();
return;
}
}
/** Truncate the head of an undo log.
NOTE that only whole pages are freed; the header page is not
freed, but emptied, if all the records there are below the limit.
@param[in,out] rseg rollback segment
@param[in] hdr_page_no header page number
@param[in] hdr_offset header offset on the page
@param[in] limit first undo number to preserve
(everything below the limit will be truncated) */
void
trx_undo_truncate_start(
trx_rseg_t* rseg,
uint32_t hdr_page_no,
uint16_t hdr_offset,
undo_no_t limit)
{
trx_undo_rec_t* rec;
trx_undo_rec_t* last_rec;
mtr_t mtr;
ut_ad(mutex_own(&(rseg->mutex)));
if (!limit) {
return;
}
loop:
mtr_start(&mtr);
if (!rseg->is_persistent()) {
mtr.set_log_mode(MTR_LOG_NO_REDO);
}
buf_block_t* undo_page;
rec = trx_undo_get_first_rec(*rseg->space, hdr_page_no, hdr_offset,
RW_X_LATCH, undo_page, &mtr);
if (rec == NULL) {
/* Already empty */
done:
mtr.commit();
return;
}
last_rec = trx_undo_page_get_last_rec(undo_page, hdr_page_no,
hdr_offset);
if (trx_undo_rec_get_undo_no(last_rec) >= limit) {
goto done;
}
if (undo_page->page.id().page_no() == hdr_page_no) {
uint16_t end = mach_read_from_2(hdr_offset + TRX_UNDO_NEXT_LOG
+ undo_page->frame);
if (end == 0) {
end = mach_read_from_2(TRX_UNDO_PAGE_HDR
+ TRX_UNDO_PAGE_FREE
+ undo_page->frame);
}
mtr.write<2>(*undo_page, undo_page->frame + hdr_offset
+ TRX_UNDO_LOG_START, end);
} else {
trx_undo_free_page(rseg, true, hdr_page_no,
undo_page->page.id().page_no(), &mtr);
}
mtr_commit(&mtr);
goto loop;
}
/** Frees an undo log segment which is not in the history list.
@param[in] undo undo log
@param[in] noredo whether the undo tablespace is redo logged */
static void trx_undo_seg_free(const trx_undo_t* undo, bool noredo)
{
ut_ad(undo->id < TRX_RSEG_N_SLOTS);
trx_rseg_t* const rseg = undo->rseg;
bool finished;
mtr_t mtr;
do {
mtr.start();
if (noredo) {
mtr.set_log_mode(MTR_LOG_NO_REDO);
}
mutex_enter(&rseg->mutex);
buf_block_t* block = trx_undo_page_get(
page_id_t(rseg->space->id, undo->hdr_page_no), &mtr);
fseg_header_t* file_seg = TRX_UNDO_SEG_HDR
+ TRX_UNDO_FSEG_HEADER + block->frame;
finished = fseg_free_step(file_seg, &mtr);
if (finished) {
/* Update the rseg header */
buf_block_t* rseg_header = trx_rsegf_get(
rseg->space, rseg->page_no, &mtr);
compile_time_assert(FIL_NULL == 0xffffffff);
mtr.memset(rseg_header, TRX_RSEG + TRX_RSEG_UNDO_SLOTS
+ undo->id * TRX_RSEG_SLOT_SIZE, 4, 0xff);
MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_USED);
}
mutex_exit(&rseg->mutex);
mtr.commit();
} while (!finished);
}
/*========== UNDO LOG MEMORY COPY INITIALIZATION =====================*/
/** Read an undo log when starting up the database.
@param[in,out] rseg rollback segment
@param[in] id rollback segment slot
@param[in] page_no undo log segment page number
@param[in,out] max_trx_id the largest observed transaction ID
@return size of the undo log in pages */
uint32_t
trx_undo_mem_create_at_db_start(trx_rseg_t *rseg, ulint id, uint32_t page_no,
trx_id_t &max_trx_id)
{
mtr_t mtr;
XID xid;
ut_ad(id < TRX_RSEG_N_SLOTS);
mtr.start();
const buf_block_t* block = trx_undo_page_get(
page_id_t(rseg->space->id, page_no), &mtr);
const ulint type = mach_read_from_2(
TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_TYPE + block->frame);
ut_ad(type == 0 || type == TRX_UNDO_INSERT || type == TRX_UNDO_UPDATE);
uint16_t state = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_STATE
+ block->frame);
uint16_t offset = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG
+ block->frame);
const trx_ulogf_t* undo_header = block->frame + offset;
/* Read X/Open XA transaction identification if it exists, or
set it to NULL. */
if (undo_header[TRX_UNDO_XID_EXISTS]) {
trx_undo_read_xid(undo_header, &xid);
} else {
xid.null();
}
trx_id_t trx_id = mach_read_from_8(undo_header + TRX_UNDO_TRX_ID);
if (trx_id > max_trx_id) {
max_trx_id = trx_id;
}
mutex_enter(&rseg->mutex);
trx_undo_t* undo = trx_undo_mem_create(
rseg, id, trx_id, &xid, page_no, offset);
mutex_exit(&rseg->mutex);
undo->dict_operation = undo_header[TRX_UNDO_DICT_TRANS];
undo->table_id = mach_read_from_8(undo_header + TRX_UNDO_TABLE_ID);
undo->size = flst_get_len(TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST
+ block->frame);
if (UNIV_UNLIKELY(state == TRX_UNDO_TO_FREE)) {
/* This is an old-format insert_undo log segment that
is being freed. The page list is inconsistent. */
ut_ad(type == TRX_UNDO_INSERT);
state = TRX_UNDO_TO_PURGE;
} else {
if (state == TRX_UNDO_TO_PURGE
|| state == TRX_UNDO_CACHED) {
trx_id_t id = mach_read_from_8(TRX_UNDO_TRX_NO
+ undo_header);
if (id > max_trx_id) {
max_trx_id = id;
}
}
fil_addr_t last_addr = flst_get_last(
TRX_UNDO_SEG_HDR + TRX_UNDO_PAGE_LIST + block->frame);
undo->last_page_no = last_addr.page;
undo->top_page_no = last_addr.page;
const buf_block_t* last = trx_undo_page_get(
page_id_t(rseg->space->id, undo->last_page_no), &mtr);
if (const trx_undo_rec_t* rec = trx_undo_page_get_last_rec(
last, page_no, offset)) {
undo->top_offset = uint16_t(rec - last->frame);
undo->top_undo_no = trx_undo_rec_get_undo_no(rec);
ut_ad(!undo->empty());
} else {
undo->top_undo_no = IB_ID_MAX;
ut_ad(undo->empty());
}
}
undo->state = state;
if (state != TRX_UNDO_CACHED) {
UT_LIST_ADD_LAST(type == TRX_UNDO_INSERT
? rseg->old_insert_list
: rseg->undo_list, undo);
} else {
UT_LIST_ADD_LAST(rseg->undo_cached, undo);
MONITOR_INC(MONITOR_NUM_UNDO_SLOT_CACHED);
}
mtr.commit();
return undo->size;
}
/********************************************************************//**
Creates and initializes an undo log memory object.
@return own: the undo log memory object */
static
trx_undo_t*
trx_undo_mem_create(
/*================*/
trx_rseg_t* rseg, /*!< in: rollback segment memory object */
ulint id, /*!< in: slot index within rseg */
trx_id_t trx_id, /*!< in: id of the trx for which the undo log
is created */
const XID* xid, /*!< in: X/Open transaction identification */
uint32_t page_no,/*!< in: undo log header page number */
uint16_t offset) /*!< in: undo log header byte offset on page */
{
trx_undo_t* undo;
ut_ad(mutex_own(&(rseg->mutex)));
ut_a(id < TRX_RSEG_N_SLOTS);
undo = static_cast<trx_undo_t*>(ut_malloc_nokey(sizeof(*undo)));
if (undo == NULL) {
return(NULL);
}
undo->id = id;
undo->state = TRX_UNDO_ACTIVE;
undo->trx_id = trx_id;
undo->xid = *xid;
undo->dict_operation = FALSE;
undo->rseg = rseg;
undo->hdr_page_no = page_no;
undo->hdr_offset = offset;
undo->last_page_no = page_no;
undo->size = 1;
undo->top_undo_no = IB_ID_MAX;
undo->top_page_no = page_no;
undo->guess_block = NULL;
undo->withdraw_clock = 0;
ut_ad(undo->empty());
return(undo);
}
/********************************************************************//**
Initializes a cached undo log object for new use. */
static
void
trx_undo_mem_init_for_reuse(
/*========================*/
trx_undo_t* undo, /*!< in: undo log to init */
trx_id_t trx_id, /*!< in: id of the trx for which the undo log
is created */
const XID* xid, /*!< in: X/Open XA transaction identification*/
uint16_t offset) /*!< in: undo log header byte offset on page */
{
ut_ad(mutex_own(&((undo->rseg)->mutex)));
ut_a(undo->id < TRX_RSEG_N_SLOTS);
undo->state = TRX_UNDO_ACTIVE;
undo->trx_id = trx_id;
undo->xid = *xid;
undo->dict_operation = FALSE;
undo->hdr_offset = offset;
undo->top_undo_no = IB_ID_MAX;
ut_ad(undo->empty());
}
/** Create an undo log.
@param[in,out] trx transaction
@param[in,out] rseg rollback segment
@param[out] undo undo log object
@param[out] err error code
@param[in,out] mtr mini-transaction
@return undo log block
@retval NULL on failure */
static MY_ATTRIBUTE((nonnull, warn_unused_result))
buf_block_t*
trx_undo_create(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** undo,
dberr_t* err, mtr_t* mtr)
{
ulint id;
ut_ad(mutex_own(&(rseg->mutex)));
buf_block_t* block = trx_undo_seg_create(
rseg->space,
trx_rsegf_get(rseg->space, rseg->page_no, mtr), &id, err, mtr);
if (!block) {
return NULL;
}
rseg->curr_size++;
uint16_t offset = trx_undo_header_create(block, trx->id, mtr);
*undo = trx_undo_mem_create(rseg, id, trx->id, trx->xid,
block->page.id().page_no(), offset);
if (*undo == NULL) {
*err = DB_OUT_OF_MEMORY;
/* FIXME: this will not free the undo block to the file */
return NULL;
} else if (rseg != trx->rsegs.m_redo.rseg) {
return block;
}
switch (trx_get_dict_operation(trx)) {
case TRX_DICT_OP_NONE:
break;
case TRX_DICT_OP_INDEX:
/* Do not discard the table on recovery. */
trx->table_id = 0;
/* fall through */
case TRX_DICT_OP_TABLE:
(*undo)->table_id = trx->table_id;
(*undo)->dict_operation = TRUE;
mtr->write<1,mtr_t::MAYBE_NOP>(*block, block->frame + offset
+ TRX_UNDO_DICT_TRANS, 1U);
mtr->write<8,mtr_t::MAYBE_NOP>(*block, block->frame + offset
+ TRX_UNDO_TABLE_ID,
trx->table_id);
}
*err = DB_SUCCESS;
return block;
}
/*================ UNDO LOG ASSIGNMENT AND CLEANUP =====================*/
/** Reuse a cached undo log block.
@param[in,out] trx transaction
@param[in,out] rseg rollback segment
@param[out] pundo the undo log memory object
@param[in,out] mtr mini-transaction
@return the undo log block
@retval NULL if none cached */
static
buf_block_t*
trx_undo_reuse_cached(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** pundo,
mtr_t* mtr)
{
ut_ad(mutex_own(&rseg->mutex));
trx_undo_t* undo = UT_LIST_GET_FIRST(rseg->undo_cached);
if (!undo) {
return NULL;
}
ut_ad(undo->size == 1);
ut_ad(undo->id < TRX_RSEG_N_SLOTS);
buf_block_t* block = buf_page_get(page_id_t(undo->rseg->space->id,
undo->hdr_page_no),
0, RW_X_LATCH, mtr);
if (!block) {
return NULL;
}
buf_block_dbg_add_level(block, SYNC_TRX_UNDO_PAGE);
UT_LIST_REMOVE(rseg->undo_cached, undo);
MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_CACHED);
*pundo = undo;
uint16_t offset = trx_undo_header_create(block, trx->id, mtr);
trx_undo_mem_init_for_reuse(undo, trx->id, trx->xid, offset);
if (rseg != trx->rsegs.m_redo.rseg) {
return block;
}
switch (trx_get_dict_operation(trx)) {
case TRX_DICT_OP_NONE:
return block;
case TRX_DICT_OP_INDEX:
/* Do not discard the table on recovery. */
trx->table_id = 0;
/* fall through */
case TRX_DICT_OP_TABLE:
undo->table_id = trx->table_id;
undo->dict_operation = TRUE;
mtr->write<1,mtr_t::MAYBE_NOP>(*block, block->frame + offset
+ TRX_UNDO_DICT_TRANS, 1U);
mtr->write<8,mtr_t::MAYBE_NOP>(*block, block->frame + offset
+ TRX_UNDO_TABLE_ID,
trx->table_id);
}
return block;
}
/** Assign an undo log for a persistent transaction.
A new undo log is created or a cached undo log reused.
@param[in,out] trx transaction
@param[out] err error code
@param[in,out] mtr mini-transaction
@return the undo log block
@retval NULL on error */
buf_block_t*
trx_undo_assign(trx_t* trx, dberr_t* err, mtr_t* mtr)
{
ut_ad(mtr->get_log_mode() == MTR_LOG_ALL);
trx_undo_t* undo = trx->rsegs.m_redo.undo;
if (undo) {
return buf_page_get_gen(
page_id_t(undo->rseg->space->id, undo->last_page_no),
0, RW_X_LATCH,
buf_pool.is_obsolete(undo->withdraw_clock)
? NULL : undo->guess_block,
BUF_GET, __FILE__, __LINE__, mtr, err);
}
trx_rseg_t* rseg = trx->rsegs.m_redo.rseg;
mutex_enter(&rseg->mutex);
buf_block_t* block = trx_undo_reuse_cached(
trx, rseg, &trx->rsegs.m_redo.undo, mtr);
if (!block) {
block = trx_undo_create(trx, rseg, &trx->rsegs.m_redo.undo,
err, mtr);
ut_ad(!block == (*err != DB_SUCCESS));
if (!block) {
goto func_exit;
}
} else {
*err = DB_SUCCESS;
}
UT_LIST_ADD_FIRST(rseg->undo_list, trx->rsegs.m_redo.undo);
func_exit:
mutex_exit(&rseg->mutex);
return block;
}
/** Assign an undo log for a transaction.
A new undo log is created or a cached undo log reused.
@param[in,out] trx transaction
@param[in] rseg rollback segment
@param[out] undo the undo log
@param[out] err error code
@param[in,out] mtr mini-transaction
@return the undo log block
@retval NULL on error */
buf_block_t*
trx_undo_assign_low(trx_t* trx, trx_rseg_t* rseg, trx_undo_t** undo,
dberr_t* err, mtr_t* mtr)
{
const bool is_temp __attribute__((unused)) = rseg == trx->rsegs.m_noredo.rseg;
ut_ad(rseg == trx->rsegs.m_redo.rseg
|| rseg == trx->rsegs.m_noredo.rseg);
ut_ad(undo == (is_temp
? &trx->rsegs.m_noredo.undo
: &trx->rsegs.m_redo.undo));
ut_ad(mtr->get_log_mode()
== (is_temp ? MTR_LOG_NO_REDO : MTR_LOG_ALL));
if (*undo) {
return buf_page_get_gen(
page_id_t(rseg->space->id, (*undo)->last_page_no),
0, RW_X_LATCH,
buf_pool.is_obsolete((*undo)->withdraw_clock)
? NULL : (*undo)->guess_block,
BUF_GET, __FILE__, __LINE__, mtr, err);
}
DBUG_EXECUTE_IF(
"ib_create_table_fail_too_many_trx",
*err = DB_TOO_MANY_CONCURRENT_TRXS; return NULL;
);
mutex_enter(&rseg->mutex);
buf_block_t* block = trx_undo_reuse_cached(trx, rseg, undo, mtr);
if (!block) {
block = trx_undo_create(trx, rseg, undo, err, mtr);
ut_ad(!block == (*err != DB_SUCCESS));
if (!block) {
goto func_exit;
}
} else {
*err = DB_SUCCESS;
}
UT_LIST_ADD_FIRST(rseg->undo_list, *undo);
func_exit:
mutex_exit(&rseg->mutex);
return block;
}
/******************************************************************//**
Sets the state of the undo log segment at a transaction finish.
@return undo log segment header page, x-latched */
buf_block_t*
trx_undo_set_state_at_finish(
/*=========================*/
trx_undo_t* undo, /*!< in: undo log memory copy */
mtr_t* mtr) /*!< in: mtr */
{
ut_a(undo->id < TRX_RSEG_N_SLOTS);
buf_block_t* block = trx_undo_page_get(
page_id_t(undo->rseg->space->id, undo->hdr_page_no), mtr);
const uint16_t state = undo->size == 1
&& TRX_UNDO_PAGE_REUSE_LIMIT
> mach_read_from_2(TRX_UNDO_PAGE_HDR + TRX_UNDO_PAGE_FREE
+ block->frame)
? TRX_UNDO_CACHED
: TRX_UNDO_TO_PURGE;
undo->state = state;
mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE
+ block->frame, state);
return block;
}
/** Set the state of the undo log segment at a XA PREPARE or XA ROLLBACK.
@param[in,out] trx transaction
@param[in,out] undo undo log
@param[in] rollback false=XA PREPARE, true=XA ROLLBACK
@param[in,out] mtr mini-transaction
@return undo log segment header page, x-latched */
void trx_undo_set_state_at_prepare(trx_t *trx, trx_undo_t *undo, bool rollback,
mtr_t *mtr)
{
ut_a(undo->id < TRX_RSEG_N_SLOTS);
buf_block_t* block = trx_undo_page_get(
page_id_t(undo->rseg->space->id, undo->hdr_page_no), mtr);
if (rollback) {
ut_ad(undo->state == TRX_UNDO_PREPARED);
mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE
+ block->frame, TRX_UNDO_ACTIVE);
return;
}
/*------------------------------*/
ut_ad(undo->state == TRX_UNDO_ACTIVE);
undo->state = TRX_UNDO_PREPARED;
undo->xid = *trx->xid;
/*------------------------------*/
mtr->write<2>(*block, TRX_UNDO_SEG_HDR + TRX_UNDO_STATE + block->frame,
undo->state);
uint16_t offset = mach_read_from_2(TRX_UNDO_SEG_HDR + TRX_UNDO_LAST_LOG
+ block->frame);
mtr->write<1>(*block, block->frame + offset + TRX_UNDO_XID_EXISTS, 1U);
trx_undo_write_xid(block, offset, undo->xid, mtr);
}
/** Free an old insert or temporary undo log after commit or rollback.
The information is not needed after a commit or rollback, therefore
the data can be discarded.
@param[in,out] undo undo log
@param[in] is_temp whether this is temporary undo log */
void
trx_undo_commit_cleanup(trx_undo_t* undo, bool is_temp)
{
trx_rseg_t* rseg = undo->rseg;
ut_ad(is_temp == !rseg->is_persistent());
ut_ad(!is_temp || 0 == UT_LIST_GET_LEN(rseg->old_insert_list));
mutex_enter(&rseg->mutex);
UT_LIST_REMOVE(is_temp ? rseg->undo_list : rseg->old_insert_list,
undo);
if (undo->state == TRX_UNDO_CACHED) {
UT_LIST_ADD_FIRST(rseg->undo_cached, undo);
MONITOR_INC(MONITOR_NUM_UNDO_SLOT_CACHED);
} else {
ut_ad(undo->state == TRX_UNDO_TO_PURGE);
/* Delete first the undo log segment in the file */
mutex_exit(&rseg->mutex);
trx_undo_seg_free(undo, is_temp);
mutex_enter(&rseg->mutex);
ut_ad(rseg->curr_size > undo->size);
rseg->curr_size -= undo->size;
ut_free(undo);
}
mutex_exit(&rseg->mutex);
}
/** At shutdown, frees the undo logs of a transaction. */
void
trx_undo_free_at_shutdown(trx_t *trx)
{
if (trx_undo_t*& undo = trx->rsegs.m_redo.undo) {
switch (undo->state) {
case TRX_UNDO_PREPARED:
break;
case TRX_UNDO_CACHED:
case TRX_UNDO_TO_FREE:
case TRX_UNDO_TO_PURGE:
ut_ad(trx_state_eq(trx,
TRX_STATE_COMMITTED_IN_MEMORY));
/* fall through */
case TRX_UNDO_ACTIVE:
/* trx_t::commit_state() assigns
trx->state = TRX_STATE_COMMITTED_IN_MEMORY. */
ut_a(!srv_was_started
|| srv_read_only_mode
|| srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO
|| srv_fast_shutdown);
break;
default:
ut_error;
}
UT_LIST_REMOVE(trx->rsegs.m_redo.rseg->undo_list, undo);
ut_free(undo);
undo = NULL;
}
if (trx_undo_t*& undo = trx->rsegs.m_redo.old_insert) {
switch (undo->state) {
case TRX_UNDO_PREPARED:
break;
case TRX_UNDO_CACHED:
case TRX_UNDO_TO_FREE:
case TRX_UNDO_TO_PURGE:
ut_ad(trx_state_eq(trx,
TRX_STATE_COMMITTED_IN_MEMORY));
/* fall through */
case TRX_UNDO_ACTIVE:
/* trx_t::commit_state() assigns
trx->state = TRX_STATE_COMMITTED_IN_MEMORY. */
ut_a(!srv_was_started
|| srv_read_only_mode
|| srv_force_recovery >= SRV_FORCE_NO_TRX_UNDO
|| srv_fast_shutdown);
break;
default:
ut_error;
}
UT_LIST_REMOVE(trx->rsegs.m_redo.rseg->old_insert_list, undo);
ut_free(undo);
undo = NULL;
}
if (trx_undo_t*& undo = trx->rsegs.m_noredo.undo) {
ut_a(undo->state == TRX_UNDO_PREPARED);
UT_LIST_REMOVE(trx->rsegs.m_noredo.rseg->undo_list, undo);
ut_free(undo);
undo = NULL;
}
}
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