The warning was originally added in
commit c67663054a
(MySQL 4.1.12, 5.0.3) to trace claimed undo log corruption that
was analyzed in https://lists.mysql.com/mysql/176250
on November 9, 2004.
Originally, the limit was 20,000 undo log headers or transactions,
but in commit 9d6d1902e0
in MySQL 5.5.11 it was increased to 2,000,000.
The message can be triggered when the progress of purge is prevented
by a long-running transaction (or just an idle transaction whose
read view was started a long time ago), by running many transactions
that UPDATE or DELETE some records, then starting another transaction
with a read view, and finally by executing more than 2,000,000
transactions that UPDATE or DELETE records in InnoDB tables. Finally,
when the oldest long-running transaction is completed, purge would
run up to the next-oldest transaction, and there would still be more
than 2,000,000 transactions to purge.
Because the message can be triggered when the database is obviously
not corrupted, it should be removed. Heavy users of InnoDB should be
monitoring the "History list length" in SHOW ENGINE INNODB STATUS;
there is no need to spam the error log.
trx_undo_rec_get_partial_row(): When the PRIMARY KEY includes a
column prefix of an externally stored column, the already parsed
part of the undo log record may contain a reference to
an off-page column. This is the case in the bug58912 test in
innodb.innodb.
This is a regression caused by MDEV-14051 'Undo log record is too big.'
Purge in the secondary index is wrongly skipped in
row_purge_upd_exist_or_extern() because node->row only does not contain all
indexed columns.
trx_undo_rec_get_partial_row(): Add the parameter for node->update
so that the updated columns will be copied from the initial part
of the undo log record.
These assertions were disabled in MariaDB 10.1.1 in
commit df4dd593f2
with a bogus comment referring to the function wsrep_fake_trx_id()
that was introduced in the very same commit.
trx_roll_must_shutdown(): During the rollback of recovered transactions,
report progress and check if the rollback should be interrupted because
of a pending shutdown.
trx_roll_max_undo_no, trx_roll_progress_printed_pct: Remove, along with
the messages that were interleaved with other messages.
row_undo_step(), trx_rollback_active(): Abort the rollback of a
recovered ordinary transaction if fast shutdown has been initiated.
trx_rollback_resurrected(): Convert an aborted-rollback transaction
into a fake XA PREPARE transaction, so that fast shutdown can proceed.
trx_rollback_resurrected(): If shutdown was initiated, fake all
remaining active transactions to XA PREPARE state, so that shutdown
can proceed. Also, make the parameter "all" an output that will be
assigned to FALSE in this case.
trx_rollback_or_clean_recovered(): Remove the shutdown check
(it was moved to trx_rollback_resurrected()).
trx_undo_free_prepared(): Relax assertions.
If InnoDB or XtraDB recovered committed transactions at server
startup, but the processing of recovered transactions was
prevented by innodb_read_only or by innodb_force_recovery,
an assertion would fail at shutdown.
This bug was originally reproduced when Mariabackup executed
InnoDB shutdown after preparing (applying redo log into) a backup.
trx_free_prepared(): Allow TRX_STATE_COMMITTED_IN_MEMORY.
trx_undo_free_prepared(): Allow any undo log state. For transactions
that were resurrected in TRX_STATE_COMMITTED_IN_MEMORY
the undo log state would have been reset by trx_undo_set_state_at_finish().
Replace all references in InnoDB and XtraDB error log messages
to bugs.mysql.com with references to https://jira.mariadb.org/.
The original merge
commit 4274d0bf57
was accidentally reverted by the subsequent merge
commit 3b35d745c3
InnoDB was writing unnecessary information to the
update undo log records. Most notably, if an indexed column is updated,
the old value of the column would be logged twice: first as part of
the update vector, and then another time because it is an indexed column.
Because the InnoDB undo log record must fit in a single page,
this would cause unnecessary failure of certain updates.
Even after this fix, InnoDB still seems to be unnecessarily logging
indexed column values for non-updated columns. It seems that non-updated
secondary index columns only need to be logged when a PRIMARY KEY
column is updated. To reduce risk, we are not fixing this remaining flaw
in GA versions.
trx_undo_page_report_modify(): Log updated indexed columns only once.
Skip rollback and other redo-log-generating tasks if
srv_apply_log_only is set.
Instead of assigning the debug variable recv_no_log_write = FALSE,
assign it to srv_apply_log_only, so that any unwanted writes are caught.
Problem was incorrect definition of wsrep_recovery,
trx_sys_update_wsrep_checkpoint and
trx_sys_read_wsrep_checkpoint functions causing
innodb_plugin not to load as there was undefined symbols.
When MySQL 5.0.3 introduced InnoDB support for two-phase commit,
it also introduced the questionable logic to roll back XA PREPARE
transactions on startup when innodb_force_recovery is 1 or 2.
Remove this logic in order to avoid unwanted side effects when
innodb_force_recovery is being set for other reasons. That is,
XA PREPARE transactions will always remain in that state until
InnoDB receives an explicit XA ROLLBACK or XA COMMIT request
from the upper layer.
At the time the logic was introduced in MySQL 5.0.3, there already
was a startup parameter that is the preferred way of achieving
the behaviour: --tc-heuristic-recover=ROLLBACK.
Problem was that 4k page size is not really supported in
Galera. For reference see:
codership/galera#398
Page size 4k is problematic because WSREP XID info location
that was set to constant UNIV_PAGE_SIZE - 3500 and that is conflicting
with rseg undo slots location if there is lot of undo tablespaces.
Undo tablespace identifiers and page numbers require
at least 126*8=1024 bytes starting from offset 56. Therefore,
WSREP XID startig from offset 596 would overwrite several
space_id,page_no pairs starting from 72th undo log tablespace
space_id,page_no pair at offset 594.
This will cause InnoDB startup failure seen as
[ERROR] InnoDB: Unable to open undo tablespace './undo30579'.
Originally, the undo tablespace ID would always be between
0 and 127. Starting with MySQL 5.6.36 which introduced
Bug #25551311 BACKPORT BUG #23517560 REMOVE SPACE_ID RESTRICTION
FOR UNDO TABLESPACES (merged to MariaDB 10.0.31)
it is possible for an undo tablespace ID to be 0x7773. But in
this case, the page number should be 3, not 0x72650003.
This is just the first collision. The WSREP XID data would
overwrite subsequent slots.
trx0sys.h
trx0sys.cc
Code formatting and add comments.
When a slow shutdown is performed soon after spawning some work for
background threads that can create or commit transactions, it is possible
that new transactions are started or committed after the purge has finished.
This is violating the specification of innodb_fast_shutdown=0, namely that
the purge must be completed. (None of the history of the recent transactions
would be purged.)
Also, it is possible that the purge threads would exit in slow shutdown
while there exist active transactions, such as recovered incomplete
transactions that are being rolled back. Thus, the slow shutdown could
fail to purge some undo log that becomes purgeable after the transaction
commit or rollback.
srv_undo_sources: A flag that indicates if undo log can be generated
or the persistent, whether by background threads or by user SQL.
Even when this flag is clear, active transactions that already exist
in the system may be committed or rolled back.
innodb_shutdown(): Renamed from innobase_shutdown_for_mysql().
Do not return an error code; the operation never fails.
Clear the srv_undo_sources flag, and also ensure that the background
DROP TABLE queue is empty.
srv_purge_should_exit(): Do not allow the purge to exit if
srv_undo_sources are active or the background DROP TABLE queue is not
empty, or in slow shutdown, if any active transactions exist
(and are being rolled back).
srv_purge_coordinator_thread(): Remove some previous workarounds
for this bug.
innobase_start_or_create_for_mysql(): Set buf_page_cleaner_is_active
and srv_dict_stats_thread_active directly. Set srv_undo_sources before
starting the purge subsystem, to prevent immediate shutdown of the purge.
Create dict_stats_thread and fts_optimize_thread immediately
after setting srv_undo_sources, so that shutdown can use this flag to
determine if these subsystems were started.
dict_stats_shutdown(): Shut down dict_stats_thread. Backported from 10.2.
srv_shutdown_table_bg_threads(): Remove (unused).
The doublewrite buffer pages must fit in the first InnoDB system
tablespace data file. The checks that were added in the initial patch
(commit 112b21da37)
were at too high level and did not cover all cases.
innodb.log_data_file_size: Test all innodb_page_size combinations.
fsp_header_init(): Never return an error. Move the change buffer creation
to the only caller that needs to do it.
btr_create(): Clean up the logic. Remove the error log messages.
buf_dblwr_create(): Try to return an error on non-fatal failure.
Check that the first data file is big enough for creating the
doublewrite buffers.
buf_dblwr_process(): Check if the doublewrite buffer is available.
Display the message only if it is available.
recv_recovery_from_checkpoint_start_func(): Remove a redundant message
about FIL_PAGE_FILE_FLUSH_LSN mismatch when crash recovery has already
been initiated.
fil_report_invalid_page_access(): Simplify the message.
fseg_create_general(): Do not emit messages to the error log.
innobase_init(): Revert the changes.
trx_rseg_create(): Refactor (no functional change).
Problem was that all doublewrite buffer pages must fit to first
system datafile.
Ported commit 27a34df7882b1f8ed283f22bf83e8bfc523cbfde
Author: Shaohua Wang <shaohua.wang@oracle.com>
Date: Wed Aug 12 15:55:19 2015 +0800
BUG#21551464 - SEGFAULT WHILE INITIALIZING DATABASE WHEN
INNODB_DATA_FILE SIZE IS SMALL
To 10.1 (with extended error printout).
btr_create(): If ibuf header page allocation fails report error and
return FIL_NULL. Similarly if root page allocation fails return a error.
dict_build_table_def_step: If fsp_header_init fails return
error code.
fsp_header_init: returns true if header initialization succeeds
and false if not.
fseg_create_general: report error if segment or page allocation fails.
innobase_init: If first datafile is smaller than 3M and could not
contain all doublewrite buffer pages report error and fail to
initialize InnoDB plugin.
row_truncate_table_for_mysql: report error if fsp header init
fails.
srv_init_abort: New function to report database initialization errors.
srv_undo_tablespaces_init, innobase_start_or_create_for_mysql: If
database initialization fails report error and abort.
trx_rseg_create: If segment header creation fails return.
Significantly reduce the amount of InnoDB, XtraDB and Mariabackup
code changes by defining pfs_os_file_t as something that is
transparently compatible with os_file_t.
