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MDEV-26445 innodb_undo_log_truncate is unnecessarily slow

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trx_purge_truncate_history(): Do not force a write of the undo tablespace
that is being truncated. Instead, prevent page writes by acquiring
an exclusive latch on all dirty pages of the tablespace.

fseg_create(): Relax an assertion that could fail if a dirty undo page
is being initialized during undo tablespace truncation (and
trx_purge_truncate_history() already acquired an exclusive latch on it).

fsp_page_create(): If we are truncating a tablespace, try to reuse
a page that we may have already latched exclusively (because it was
in buf_pool.flush_list). To some extent, this helps the test
innodb.undo_truncate,16k to avoid running out of buffer pool.

mtr_t::commit_shrink(): Mark as clean all pages that are outside the
new bounds of the tablespace, and only add the newly reinitialized pages
to the buf_pool.flush_list.

buf_page_create(): Do not unnecessarily invoke change buffer merge on
undo tablespaces.

buf_page_t::clear_oldest_modification(bool temporary): Move some
assertions to the caller buf_page_write_complete().

innodb.undo_truncate: Use a bigger innodb_buffer_pool_size=24M.
On my system, it would otherwise hang 1 out of 1547 attempts
(on the 40th repeat of innodb.undo_truncate,16k).
Other page sizes were not affected.
This commit is contained in:
Marko Mäkelä 2021-09-24 08:24:03 +03:00
parent f5fddae3cb
commit f5794e1dc6
8 changed files with 292 additions and 241 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
mysql-test/suite/innodb/t/undo_truncate.opt Normal file
View File

@ -0,0 +1 @@
--innodb-buffer-pool-size=24M

16
mysql-test/suite/innodb/t/undo_truncate.test
View File

@ -3,6 +3,10 @@
--source include/have_undo_tablespaces.inc
--source include/have_sequence.inc
--disable_query_log
call mtr.add_suppression("InnoDB: Difficult to find free blocks in the buffer pool");
--enable_query_log
SET @save_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
SET @save_truncate = @@GLOBAL.innodb_undo_log_truncate;
SET GLOBAL innodb_undo_log_truncate = 0;
@ -46,17 +50,5 @@ drop table t1, t2;
--source include/wait_all_purged.inc
# Truncation will normally not occur with innodb_page_size=64k,
# and occasionally not with innodb_page_size=32k,
# because the undo log will not grow enough.
# TODO: For some reason this does not occur on 4k either!
if (`select @@innodb_page_size IN (8192,16384)`)
{
let $wait_condition = (SELECT variable_value!=@trunc_start
FROM information_schema.global_status
WHERE variable_name = 'innodb_undo_truncations');
source include/wait_condition.inc;
}
SET GLOBAL innodb_purge_rseg_truncate_frequency = @save_frequency;
SET GLOBAL innodb_undo_log_truncate = @save_truncate;

1
storage/innobase/buf/buf0buf.cc
View File

@ -3796,6 +3796,7 @@ loop:
/* Delete possible entries for the page from the insert buffer:
such can exist if the page belonged to an index which was dropped */
if (page_id < page_id_t{SRV_SPACE_ID_UPPER_BOUND, 0} &&
!srv_is_undo_tablespace(page_id.space()) &&
!recv_recovery_is_on())
ibuf_merge_or_delete_for_page(nullptr, page_id, zip_size);

2
storage/innobase/buf/buf0flu.cc
View File

@ -363,10 +363,12 @@ void buf_page_write_complete(const IORequest &request)
const bool temp= fsp_is_system_temporary(bpage->id().space());
mysql_mutex_lock(&buf_pool.mutex);
mysql_mutex_assert_not_owner(&buf_pool.flush_list_mutex);
buf_pool.stat.n_pages_written++;
/* While we do not need any mutex for clearing oldest_modification
here, we hope that it will be in the same cache line with io_fix,
whose changes must be protected by buf_pool.mutex. */
ut_ad(temp || bpage->oldest_modification() > 2);
bpage->clear_oldest_modification(temp);
ut_ad(bpage->io_fix() == BUF_IO_WRITE);
bpage->set_io_fix(BUF_IO_NONE);

36
storage/innobase/fsp/fsp0fsp.cc
View File

@ -1054,11 +1054,36 @@ static
buf_block_t*
fsp_page_create(fil_space_t *space, page_no_t offset, mtr_t *mtr)
{
buf_block_t *free_block= buf_LRU_get_free_block(false);
buf_block_t *block= buf_page_create(space, static_cast<uint32_t>(offset),
space->zip_size(), mtr, free_block);
buf_block_t *block, *free_block;
if (UNIV_UNLIKELY(space->is_being_truncated))
{
const page_id_t page_id{space->id, offset};
const ulint fold= page_id.fold();
mysql_mutex_lock(&buf_pool.mutex);
block= reinterpret_cast<buf_block_t*>
(buf_pool.page_hash_get_low(page_id, fold));
if (block && block->page.oldest_modification() <= 1)
block= nullptr;
mysql_mutex_unlock(&buf_pool.mutex);
if (block)
{
ut_ad(block->page.buf_fix_count() >= 1);
ut_ad(rw_lock_get_x_lock_count(&block->lock) == 1);
ut_ad(mtr->have_x_latch(*block));
free_block= block;
goto got_free_block;
}
}
free_block= buf_LRU_get_free_block(false);
got_free_block:
block= buf_page_create(space, static_cast<uint32_t>(offset),
space->zip_size(), mtr, free_block);
if (UNIV_UNLIKELY(block != free_block))
buf_pool.free_block(free_block);
fsp_init_file_page(space, block, mtr);
return block;
}
@ -1728,7 +1753,10 @@ fseg_create(fil_space_t *space, ulint byte_offset, mtr_t *mtr,
goto funct_exit;
}
ut_ad(rw_lock_get_x_lock_count(&block->lock) == 1);
ut_d(const auto x = rw_lock_get_x_lock_count(&block->lock));
ut_ad(x > 0);
ut_ad(x == 1 || space->is_being_truncated);
ut_ad(x <= 2);
ut_ad(!fil_page_get_type(block->frame));
mtr->write<1>(*block, FIL_PAGE_TYPE + 1 + block->frame,
FIL_PAGE_TYPE_SYS);

2
storage/innobase/include/buf0buf.h
View File

@ -2232,9 +2232,7 @@ inline void buf_page_t::clear_oldest_modification()
it from buf_pool.flush_list */
inline void buf_page_t::clear_oldest_modification(bool temporary)
{
mysql_mutex_assert_not_owner(&buf_pool.flush_list_mutex);
ut_ad(temporary == fsp_is_system_temporary(id().space()));
ut_ad(io_fix_ == BUF_IO_WRITE);
if (temporary)
{
ut_ad(oldest_modification() == 2);

34
storage/innobase/mtr/mtr0mtr.cc
View File

@ -459,15 +459,15 @@ void mtr_t::commit()
release_resources();
}
#ifdef UNIV_DEBUG
/** Check that all pages belong to a shrunk tablespace. */
/** Shrink a tablespace. */
struct Shrink
{
const page_id_t low, high;
Shrink(const fil_space_t &space) :
low({space.id, 0}), high({space.id, space.size}) {}
/** the first non-existing page in the tablespace */
const page_id_t high;
bool operator()(const mtr_memo_slot_t *slot) const
Shrink(const fil_space_t &space) : high({space.id, space.size}) {}
bool operator()(mtr_memo_slot_t *slot) const
{
if (!slot->object)
return true;
@ -476,29 +476,31 @@ struct Shrink
ut_ad("invalid type" == 0);
return false;
case MTR_MEMO_SPACE_X_LOCK:
ut_ad(low.space() == static_cast<fil_space_t*>(slot->object)->id);
ut_ad(high.space() == static_cast<fil_space_t*>(slot->object)->id);
return true;
case MTR_MEMO_PAGE_X_MODIFY:
case MTR_MEMO_PAGE_SX_MODIFY:
case MTR_MEMO_PAGE_X_FIX:
case MTR_MEMO_PAGE_SX_FIX:
const auto &bpage= static_cast<buf_block_t*>(slot->object)->page;
auto &bpage= static_cast<buf_block_t*>(slot->object)->page;
ut_ad(bpage.io_fix() == BUF_IO_NONE);
const auto id= bpage.id();
if (id == page_id_t{0, TRX_SYS_PAGE_NO})
if (id < high)
{
ut_ad(srv_is_undo_tablespace(low.space()));
ut_ad(id.space() == high.space() ||
(id == page_id_t{0, TRX_SYS_PAGE_NO} &&
srv_is_undo_tablespace(high.space())));
break;
}
ut_ad(id >= low);
ut_ad(id < high);
ut_ad(id.space() == high.space());
ut_ad(bpage.state() == BUF_BLOCK_FILE_PAGE);
ut_ad(bpage.oldest_modification() <= 1);
break;
if (bpage.oldest_modification() > 1)
bpage.clear_oldest_modification(false);
slot->type= static_cast<mtr_memo_type_t>(slot->type & ~MTR_MEMO_MODIFY);
}
return true;
}
};
#endif
/** Commit a mini-transaction that is shrinking a tablespace.
@param space tablespace that is being shrunk */
@ -542,7 +544,7 @@ void mtr_t::commit_shrink(fil_space_t &space)
else
ut_ad(!m_freed_space);
ut_d(m_memo.for_each_block_in_reverse(CIterate<Shrink>{space}));
m_memo.for_each_block_in_reverse(CIterate<Shrink>{space});
m_memo.for_each_block_in_reverse(CIterate<const ReleaseBlocks>
(ReleaseBlocks(start_lsn, m_commit_lsn,

441
storage/innobase/trx/trx0purge.cc
View File

@ -546,253 +546,280 @@ function is called, the caller must not have any latches on undo log pages!
*/
static void trx_purge_truncate_history()
{
ut_ad(purge_sys.head <= purge_sys.tail);
purge_sys_t::iterator& head = purge_sys.head.trx_no
? purge_sys.head : purge_sys.tail;
ut_ad(purge_sys.head <= purge_sys.tail);
purge_sys_t::iterator &head= purge_sys.head.trx_no
? purge_sys.head : purge_sys.tail;
if (head.trx_no >= purge_sys.low_limit_no()) {
/* This is sometimes necessary. TODO: find out why. */
head.trx_no = purge_sys.low_limit_no();
head.undo_no = 0;
}
if (head.trx_no >= purge_sys.low_limit_no())
{
/* This is sometimes necessary. TODO: find out why. */
head.trx_no= purge_sys.low_limit_no();
head.undo_no= 0;
}
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
if (trx_rseg_t* rseg = trx_sys.rseg_array[i]) {
ut_ad(rseg->id == i);
trx_purge_truncate_rseg_history(*rseg, head);
}
}
for (ulint i= 0; i < TRX_SYS_N_RSEGS; ++i)
{
if (trx_rseg_t *rseg= trx_sys.rseg_array[i])
{
ut_ad(rseg->id == i);
trx_purge_truncate_rseg_history(*rseg, head);
}
}
if (srv_undo_tablespaces_active < 2) {
return;
}
if (srv_undo_tablespaces_active < 2)
return;
while (srv_undo_log_truncate) {
if (!purge_sys.truncate.current) {
const ulint threshold = ulint(srv_max_undo_log_size
>> srv_page_size_shift);
for (ulint i = purge_sys.truncate.last
? purge_sys.truncate.last->id
- srv_undo_space_id_start
: 0, j = i;; ) {
ulint space_id = srv_undo_space_id_start + i;
ut_ad(srv_is_undo_tablespace(space_id));
fil_space_t* space= fil_space_get(space_id);
while (srv_undo_log_truncate)
{
if (!purge_sys.truncate.current)
{
const ulint threshold=
ulint(srv_max_undo_log_size >> srv_page_size_shift);
for (ulint i= purge_sys.truncate.last
? purge_sys.truncate.last->id - srv_undo_space_id_start : 0,
j= i;; )
{
const auto space_id= srv_undo_space_id_start + i;
ut_ad(srv_is_undo_tablespace(space_id));
fil_space_t *space= fil_space_get(space_id);
ut_a(UT_LIST_GET_LEN(space->chain) == 1);
if (space && space->get_size() > threshold) {
purge_sys.truncate.current = space;
break;
}
if (space && space->get_size() > threshold)
{
purge_sys.truncate.current= space;
break;
}
++i;
i %= srv_undo_tablespaces_active;
if (i == j) {
break;
}
}
}
++i;
i %= srv_undo_tablespaces_active;
if (i == j)
return;
}
}
if (!purge_sys.truncate.current) {
return;
}
fil_space_t &space= *purge_sys.truncate.current;
/* Undo tablespace always are a single file. */
fil_node_t *file= UT_LIST_GET_FIRST(space.chain);
/* The undo tablespace files are never closed. */
ut_ad(file->is_open());
fil_space_t& space = *purge_sys.truncate.current;
/* Undo tablespace always are a single file. */
ut_a(UT_LIST_GET_LEN(space.chain) == 1);
fil_node_t* file = UT_LIST_GET_FIRST(space.chain);
/* The undo tablespace files are never closed. */
ut_ad(file->is_open());
DBUG_LOG("undo", "marking for truncate: " << file->name);
DBUG_LOG("undo", "marking for truncate: " << file->name);
for (ulint i= 0; i < TRX_SYS_N_RSEGS; ++i)
if (trx_rseg_t *rseg= trx_sys.rseg_array[i])
if (rseg->space == &space)
/* Once set, this rseg will not be allocated to subsequent
transactions, but we will wait for existing active
transactions to finish. */
rseg->skip_allocation= true;
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
if (trx_rseg_t* rseg = trx_sys.rseg_array[i]) {
ut_ad(rseg->is_persistent());
if (rseg->space == &space) {
/* Once set, this rseg will
not be allocated to subsequent
transactions, but we will wait
for existing active
transactions to finish. */
rseg->skip_allocation = true;
}
}
}
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
trx_rseg_t* rseg = trx_sys.rseg_array[i];
if (!rseg || rseg->space != &space) {
continue;
}
mutex_enter(&rseg->mutex);
ut_ad(rseg->skip_allocation);
if (rseg->trx_ref_count) {
for (ulint i= 0; i < TRX_SYS_N_RSEGS; ++i)
{
trx_rseg_t *rseg= trx_sys.rseg_array[i];
if (!rseg || rseg->space != &space)
continue;
mutex_enter(&rseg->mutex);
ut_ad(rseg->skip_allocation);
ut_ad(rseg->is_persistent());
if (rseg->trx_ref_count)
{
not_free:
mutex_exit(&rseg->mutex);
return;
}
mutex_exit(&rseg->mutex);
return;
}
if (rseg->curr_size != 1) {
/* Check if all segments are
cached and safe to remove. */
ulint cached = 0;
if (rseg->curr_size != 1)
{
/* Check if all segments are cached and safe to remove. */
ulint cached= 0;
for (trx_undo_t *undo= UT_LIST_GET_FIRST(rseg->undo_cached); undo;
undo= UT_LIST_GET_NEXT(undo_list, undo))
{
if (head.trx_no < undo->trx_id)
goto not_free;
else
cached+= undo->size;
}
for (trx_undo_t* undo = UT_LIST_GET_FIRST(
rseg->undo_cached);
undo;
undo = UT_LIST_GET_NEXT(undo_list,
undo)) {
if (head.trx_no < undo->trx_id) {
goto not_free;
} else {
cached += undo->size;
}
}
ut_ad(rseg->curr_size > cached);
ut_ad(rseg->curr_size > cached);
if (rseg->curr_size > cached + 1)
goto not_free;
}
if (rseg->curr_size > cached + 1) {
goto not_free;
}
}
mutex_exit(&rseg->mutex);
}
mutex_exit(&rseg->mutex);
}
ib::info() << "Truncating " << file->name;
trx_purge_cleanse_purge_queue(space);
ib::info() << "Truncating " << file->name;
trx_purge_cleanse_purge_queue(space);
log_free_check();
/* Flush all to-be-discarded pages of the tablespace.
mtr_t mtr;
mtr.start();
mtr_x_lock_space(&space, &mtr);
During truncation, we do not want any writes to the
to-be-discarded area, because we must set the space.size
early in order to have deterministic page allocation.
/* Lock all modified pages of the tablespace.
If a log checkpoint was completed at LSN earlier than our
mini-transaction commit and the server was killed, then
discarding the to-be-trimmed pages without flushing would
break crash recovery. So, we cannot avoid the write. */
while (buf_flush_list_space(&space));
During truncation, we do not want any writes to the file.
log_free_check();
If a log checkpoint was completed at LSN earlier than our
mini-transaction commit and the server was killed, then
discarding the to-be-trimmed pages without flushing would
break crash recovery. */
mysql_mutex_lock(&buf_pool.flush_list_mutex);
/* Adjust the tablespace metadata. */
if (!fil_truncate_prepare(space.id)) {
ib::error() << "Failed to find UNDO tablespace "
<< file->name;
return;
}
for (buf_page_t *bpage= UT_LIST_GET_LAST(buf_pool.flush_list); bpage; )
{
ut_ad(bpage->oldest_modification());
ut_ad(bpage->in_file());
/* Re-initialize tablespace, in a single mini-transaction. */
mtr_t mtr;
const ulint size = SRV_UNDO_TABLESPACE_SIZE_IN_PAGES;
mtr.start();
mtr_x_lock_space(purge_sys.truncate.current, &mtr);
/* Associate the undo tablespace with mtr.
During mtr::commit(), InnoDB can use the undo
tablespace object to clear all freed ranges */
mtr.set_named_space(purge_sys.truncate.current);
mtr.trim_pages(page_id_t(space.id, size));
fsp_header_init(purge_sys.truncate.current, size, &mtr);
mutex_enter(&fil_system.mutex);
purge_sys.truncate.current->size = file->size = size;
mutex_exit(&fil_system.mutex);
buf_page_t *prev= UT_LIST_GET_PREV(list, bpage);
buf_block_t* sys_header = trx_sysf_get(&mtr);
if (bpage->id().space() == space.id &&
bpage->oldest_modification() != 1)
{
ut_ad(bpage->state() == BUF_BLOCK_FILE_PAGE);
auto block= reinterpret_cast<buf_block_t*>(bpage);
block->fix();
ut_ad(rw_lock_s_lock_nowait(block->debug_latch, __FILE__, __LINE__));
buf_pool.flush_hp.set(prev);
mysql_mutex_unlock(&buf_pool.flush_list_mutex);
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
trx_rseg_t* rseg = trx_sys.rseg_array[i];
if (!rseg || rseg->space != &space) {
continue;
}
#ifdef BTR_CUR_HASH_ADAPT
ut_ad(!block->index); /* There is no AHI on undo tablespaces. */
#endif
rw_lock_x_lock(&block->lock);
mysql_mutex_lock(&buf_pool.flush_list_mutex);
ut_ad(bpage->io_fix() == BUF_IO_NONE);
ut_ad(rseg->is_persistent());
ut_d(const ulint old_page = rseg->page_no);
if (bpage->oldest_modification() > 1)
{
bpage->clear_oldest_modification(false);
mtr.memo_push(block, MTR_MEMO_PAGE_X_FIX);
}
else
{
rw_lock_x_unlock(&block->lock);
block->unfix();
}
buf_block_t* rblock = trx_rseg_header_create(
purge_sys.truncate.current,
rseg->id, sys_header, &mtr);
ut_ad(rblock);
rseg->page_no = rblock
? rblock->page.id().page_no() : FIL_NULL;
ut_ad(old_page == rseg->page_no);
if (prev != buf_pool.flush_hp.get())
{
/* Rescan, because we may have lost the position. */
bpage= UT_LIST_GET_LAST(buf_pool.flush_list);
continue;
}
}
/* Before re-initialization ensure that we
free the existing structure. There can't be
any active transactions. */
ut_a(UT_LIST_GET_LEN(rseg->undo_list) == 0);
bpage= prev;
}
trx_undo_t* next_undo;
mysql_mutex_unlock(&buf_pool.flush_list_mutex);
for (trx_undo_t* undo = UT_LIST_GET_FIRST(
rseg->undo_cached);
undo; undo = next_undo) {
/* Adjust the tablespace metadata. */
if (!fil_truncate_prepare(space.id))
{
ib::error() << "Failed to find UNDO tablespace " << file->name;
mtr.commit();
return;
}
next_undo = UT_LIST_GET_NEXT(undo_list, undo);
UT_LIST_REMOVE(rseg->undo_cached, undo);
MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_CACHED);
ut_free(undo);
}
/* Re-initialize tablespace, in a single mini-transaction. */
const ulint size= SRV_UNDO_TABLESPACE_SIZE_IN_PAGES;
/* Associate the undo tablespace with mtr.
During mtr::commit_shrink(), InnoDB can use the undo
tablespace object to clear all freed ranges */
mtr.set_named_space(&space);
mtr.trim_pages(page_id_t(space.id, size));
fsp_header_init(&space, size, &mtr);
mutex_enter(&fil_system.mutex);
space.size= file->size= size;
mutex_exit(&fil_system.mutex);
UT_LIST_INIT(rseg->undo_list,
&trx_undo_t::undo_list);
UT_LIST_INIT(rseg->undo_cached,
&trx_undo_t::undo_list);
buf_block_t *sys_header= trx_sysf_get(&mtr);
/* These were written by trx_rseg_header_create(). */
ut_ad(!mach_read_from_4(TRX_RSEG + TRX_RSEG_FORMAT
+ rblock->frame));
ut_ad(!mach_read_from_4(TRX_RSEG + TRX_RSEG_HISTORY_SIZE
+ rblock->frame));
for (ulint i= 0; i < TRX_SYS_N_RSEGS; ++i)
{
trx_rseg_t *rseg= trx_sys.rseg_array[i];
if (!rseg || rseg->space != &space)
continue;
/* Initialize the undo log lists according to
the rseg header */
rseg->curr_size = 1;
rseg->trx_ref_count = 0;
rseg->last_page_no = FIL_NULL;
rseg->last_commit_and_offset = 0;
rseg->needs_purge = false;
}
ut_ad(rseg->id == i);
ut_ad(rseg->is_persistent());
ut_d(const auto old_page= rseg->page_no);
mtr.commit_shrink(space);
buf_block_t *rblock= trx_rseg_header_create(&space, i, sys_header, &mtr);
ut_ad(rblock);
rseg->page_no= rblock ? rblock->page.id().page_no() : FIL_NULL;
ut_ad(old_page == rseg->page_no);
/* No mutex; this is only updated by the purge coordinator. */
export_vars.innodb_undo_truncations++;
/* Before re-initialization ensure that we free the existing
structure. There can't be any active transactions. */
ut_a(UT_LIST_GET_LEN(rseg->undo_list) == 0);
if (purge_sys.rseg != NULL
&& purge_sys.rseg->last_page_no == FIL_NULL) {
/* If purge_sys.rseg is pointing to rseg that
was recently truncated then move to next rseg
element. Note: Ideally purge_sys.rseg should
be NULL because purge should complete
processing of all the records but there is
purge_batch_size that can force the purge loop
to exit before all the records are purged and
in this case purge_sys.rseg could point to a
valid rseg waiting for next purge cycle. */
purge_sys.next_stored = false;
purge_sys.rseg = NULL;
}
for (trx_undo_t *undo= UT_LIST_GET_FIRST(rseg->undo_cached), *next_undo;
undo; undo= next_undo)
{
next_undo= UT_LIST_GET_NEXT(undo_list, undo);
UT_LIST_REMOVE(rseg->undo_cached, undo);
MONITOR_DEC(MONITOR_NUM_UNDO_SLOT_CACHED);
ut_free(undo);
}
DBUG_EXECUTE_IF("ib_undo_trunc",
ib::info() << "ib_undo_trunc";
log_buffer_flush_to_disk();
DBUG_SUICIDE(););
UT_LIST_INIT(rseg->undo_list, &trx_undo_t::undo_list);
UT_LIST_INIT(rseg->undo_cached, &trx_undo_t::undo_list);
for (ulint i = 0; i < TRX_SYS_N_RSEGS; ++i) {
if (trx_rseg_t* rseg = trx_sys.rseg_array[i]) {
ut_ad(rseg->is_persistent());
if (rseg->space == &space) {
rseg->skip_allocation = false;
}
}
}
/* These were written by trx_rseg_header_create(). */
ut_ad(!mach_read_from_4(TRX_RSEG + TRX_RSEG_FORMAT + rblock->frame));
ut_ad(!mach_read_from_4(TRX_RSEG + TRX_RSEG_HISTORY_SIZE +
rblock->frame));
/* Initialize the undo log lists according to
the rseg header */
rseg->curr_size= 1;
rseg->trx_ref_count= 0;
rseg->last_page_no= FIL_NULL;
rseg->last_commit_and_offset= 0;
rseg->needs_purge= false;
}
ib::info() << "Truncated " << file->name;
purge_sys.truncate.last = purge_sys.truncate.current;
ut_ad(&space == purge_sys.truncate.current);
purge_sys.truncate.current = NULL;
}
mtr.commit_shrink(space);
/* No mutex; this is only updated by the purge coordinator. */
export_vars.innodb_undo_truncations++;
if (purge_sys.rseg && purge_sys.rseg->last_page_no == FIL_NULL)
{
/* If purge_sys.rseg is pointing to rseg that was recently
truncated then move to next rseg element.
Note: Ideally purge_sys.rseg should be NULL because purge should
complete processing of all the records but srv_purge_batch_size
can force the purge loop to exit before all the records are purged. */
purge_sys.rseg= nullptr;
purge_sys.next_stored= false;
}
DBUG_EXECUTE_IF("ib_undo_trunc", ib::info() << "ib_undo_trunc";
log_buffer_flush_to_disk();
DBUG_SUICIDE(););
for (ulint i= 0; i < TRX_SYS_N_RSEGS; ++i)
{
if (trx_rseg_t *rseg= trx_sys.rseg_array[i])
{
ut_ad(rseg->id == i);
ut_ad(rseg->is_persistent());
if (rseg->space == &space)
rseg->skip_allocation= false;
}
}
ib::info() << "Truncated " << file->name;
purge_sys.truncate.last= purge_sys.truncate.current;
ut_ad(&space == purge_sys.truncate.current);
purge_sys.truncate.current= nullptr;
}
}
/***********************************************************************//**