The fixes in b8a6719889 have not disabled
semi-consistent read for innodb_snapshot_isolation=ON mode, they just allowed
read uncommitted version of a record, that's why the test for MDEV-26643 worked
well.
The semi-consistent read should be disabled on upper level in
row_search_mvcc() for READ COMMITTED isolation level.
Reviewed by Marko Mäkelä.
- InnoDB tries to write FILE_CHECKPOINT marker during
early recovery when log file size is insufficient.
While updating the log checkpoint at the end of the recovery,
InnoDB must already have written out all pending changes
to the persistent files. To complete the checkpoint, InnoDB
has to write some log records for the checkpoint and to
update the checkpoint header. If the server gets killed
before updating the checkpoint header then it would lead
the logfile to be unrecoverable.
- This patch avoids FILE_CHECKPOINT marker during early
recovery and narrows down the window of opportunity to
make the log file unrecoverable.
- The deadlock counter was moved from
Deadlock::find_cycle into Deadlock::report, because
the find_cycle method is called multiple times during deadlock
detection flow, which means it shouldn't have such side effects.
But report() can, which called only once for
a victim transaction.
- Also the deadlock_detect.test and *.result test case
has been extended to handle the fix.
number of non-user tablespace.
fil_space_t::try_to_close(): Don't try to close
the tablespace which is acquired by the caller of
the function
Added the suppression message in open_files_limit test case
number of non-user tablespace.
- InnoDB only closes the user tablespace when the number of open
files exceeds innodb_open_files limit. In that case, InnoDB should
make sure that innodb_open_files value should be greater
than number of undo tablespace, system and temporary tablespace files.
When checkpoint age goes beyond the sync flush threshold and
buf_flush_sync_lsn is set, page cleaner enters into "furious flush"
stage to aggressively flush dirty pages from flush list and pull
checkpoint LSN above safe margin. In this stage, page cleaner skips
doing LRU flush and eviction.
In 10.6, all other threads entirely rely on page cleaner to generate
free pages. If free pages get over while page cleaner is busy in
"furious flush" stage, a session thread could wait for free page in the
middle of a min-transaction(mtr) while holding latches on other pages.
It, in turn, can prevent page cleaner to flush such pages preventing
checkpoint LSN to move forward creating a deadlock situation. Even
otherwise, it could create a stall and hang like situation for large BP
with plenty of dirty pages to flush before the stage could finish.
Fix: During furious flush, check and evict LRU pages after each flush
iteration.
- Added a counter innodb_num_bulk_insert_operation in
INFORMATION_SCHEMA.GLOBAL_STATUS. This counter is incremented
whenever a InnoDB undergoes bulk insert operation.
- Change the innodb_instant_alter_column to atomic variable.
tablespace truncation
- InnoDB fails with out of bound write error after temporary
tablespace truncation. This issue caused by
commit c507678b20 (MDEV-28699).
InnoDB fail to clear freed ranges if shrinking size
is the last offset of the freed range.
- InnoDB page compression works only on COMPACT or DYNAMIC row
format tables. So InnoDB should throw error when alter table
tries to enable PAGE_COMPRESSED for redundant table.
in buf_dblwr_t::init_or_load_pages()
- InnoDB fails to set the TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED
flag in transaction system header page while recreating
the undo log tablespaces
buf_dblwr_t::init_or_load_pages(): Tries to reset the
space id and try to write into doublewrite buffer even
when read_only mode is enabled.
In srv_all_undo_tablespaces_open(), InnoDB should try to
open the extra unused undo tablespaces instead of trying to
creating it.
in buf_dblwr_t::init_or_load_pages()
- InnoDB fails to set the TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED
flag in transaction system header page while recreating
the undo log tablespaces
buf_dblwr_t::init_or_load_pages(): Tries to reset the
space id and try to write into doublewrite buffer even
when read_only mode is enabled.
In srv_all_undo_tablespaces_open(), InnoDB should try to
open the extra unused undo tablespaces instead of trying to
creating it.
BUF_LRU_MIN_LEN (256) is too high value for low buffer pool(BP) size.
For example, for BP size lower than 80M and 16 K page size, the limit is
more than 5% of total BP and for lowest BP 5M, it is 80% of the BP.
Non-data objects like explicit locks could occupy part of the BP pool
reducing the pages available for LRU. If LRU reaches minimum limit and
if no free pages are available, server would hang with page cleaner not
able to free any more pages.
Fix: To avoid such hang, we adjust the LRU limit lower than the limit
for data objects as checked in buf_LRU_check_size_of_non_data_objects()
i.e. one page less than 5% of BP.
trx_free_at_shutdown(): Similar to trx_t::commit_in_memory(),
clear the detailed_error (FOREIGN KEY constraint error) before
invoking trx_t::free(). We only do this on debug instrumented
builds in order to avoid a debug assertion failure on shutdown.
This regression is introduced in 10.6 by following commit.
commit 898dcf93a8
(Cleanup the lock creation)
It removed one important optimization for lock bitmap pre-allocation.
We pre-allocate about 8 byte extra space along with every lock object to
adjust for similar locks on newly created records on the same page by
same transaction. When it is exhausted, a new lock object is created
with similar 8 byte pre-allocation. With this optimization removed we
are left with only 1 byte pre-allocation. When large number of records
are inserted and locked in a single page, we end up creating too many
new locks almost in n^2 order.
Fix-1: Bring back LOCK_PAGE_BITMAP_MARGIN for pre-allocation.
Fix-2: Use the extra space (40 bytes) for bitmap in trx->lock.rec_pool.
Problem:
=======
During InnoDB non-rebuild online alter operation, InnoDB set the
dummy log to clustered index online log. This can be used by
concurrent DML to identify whether the table undergoes online DDL.
InnoDB fails to reset the dummy log of clustered index in case
of error happened during prepare phase.
Solution:
========
Reset the InnoDB clustered index online log in case of error during
prepare phase.
Problem:
========
- InnoDB wrongly calulates the record size in
btr_node_ptr_max_size() when prefix index of
the column has to be stored externally.
Fix:
====
- InnoDB should add the maximum field size to
record size when the field is a fixed length one.
commit_try_norebuild(): Add the parameter statistics_exist,
similar to commit_try_rebuild(). If the InnoDB statistics tables
did not exist, we will not attempt to update statistics later on
during the transaction.
Thanks to Matthias Leich for originally reproducing this scenario.
Problem:
========
- Partition update operation enables the bulk insert for the
transaction while moving the row between partitions. This leads
to debug assert failure while removing the row from one
of the partition.
Solution:
========
- Disallow the bulk insert operation for non-insert operation
of partition table.
In case of partition insert, InnoDB fails to end the bulk insert
for one of the partition. It leads to bulk insert operation for
the consecutive delete statement.
trx_t::bulk_insert_apply_for_table(): Irrespective of bulk insert
value, InnoDB should end the bulk insert for the table.
bulk_insert_apply_for_table(dict_table_t*)
This issue is caused by
commit 188c5da72a (MDEV-32453).
trx_t::bulk_insert_apply_for_table(): Remove the assert
check_unique_secondary and check_foreigns. InnoDB can
apply the bulk insert operation even after disabling
the check_foreigns and check_unique_secondary variable.
On Windows systems, occurrences of ERROR_SHARING_VIOLATION due to
conflicting share modes between processes accessing the same file can
result in CreateFile failures.
mysys' my_open() already incorporates a workaround by implementing
wait/retry logic on Windows.
But this does not help if files are opened using shell redirection like
mysqltest traditionally did it, i.e via
--echo exec "some text" > output_file
In such cases, it is cmd.exe, that opens the output_file, and it
won't do any sharing-violation retries.
This commit addresses the issue by introducing a new built-in command,
'write_line', in mysqltest. This new command serves as a brief alternative
to 'write_file', with a single line output, that also resolves variables
like "exec" would.
Internally, this command will use my_open(), and therefore retry-on-error
logic.
Hopefully this will eliminate the very sporadic "can't open file because
it is used by another process" error on CI.
Issue:
------
The actual order of acquisition of the IBUF pessimistic insert mutex
(SYNC_IBUF_PESS_INSERT_MUTEX) and IBUF header page latch
(SYNC_IBUF_HEADER) w.r.t space latch (SYNC_FSP) differs from the order
defined in sync0types.h. It was not discovered earlier as the path to
ibuf_remove_free_page was not covered by the mtr test. Ideal order and
one defined in sync0types.h is as follows.
SYNC_IBUF_HEADER -> SYNC_IBUF_PESS_INSERT_MUTEX -> SYNC_FSP
In ibuf_remove_free_page, we acquire space latch earlier and we have
the order as follows resulting in the assert with innodb_sync_debug=on.
SYNC_FSP -> SYNC_IBUF_HEADER -> SYNC_IBUF_PESS_INSERT_MUTEX
Fix:
---
We do maintain this order in other places and there doesn't seem to be
any real issue here. To reduce impact in GA versions, we avoid doing
extensive changes in mutex ordering to match the current
SYNC_IBUF_PESS_INSERT_MUTEX order. Instead we relax the ordering check
for IBUF pessimistic insert mutex using SYNC_NO_ORDER_CHECK.
