Improve the performance of slave connect using B+-Tree indexes on each binlog
file. The index allows fast lookup of a GTID position to the corresponding
offset in the binlog file, as well as lookup of a position to find the
corresponding GTID position.
This eliminates a costly sequential scan of the starting binlog file
to find the GTID starting position when a slave connects. This is
especially costly if the binlog file is not cached in memory (IO
cost), or if it is encrypted or a lot of slaves connect simultaneously
(CPU cost).
The size of the index files is generally less than 1% of the binlog data, so
not expected to be an issue.
Most of the work writing the index is done as a background task, in
the binlog background thread. This minimises the performance impact on
transaction commit. A simple global mutex is used to protect index
reads and (background) index writes; this is fine as slave connect is
a relatively infrequent operation.
Here are the user-visible options and status variables. The feature is on by
default and is expected to need no tuning or configuration for most users.
binlog_gtid_index
On by default. Can be used to disable the indexes for testing purposes.
binlog_gtid_index_page_size (default 4096)
Page size to use for the binlog GTID index. This is the size of the nodes
in the B+-tree used internally in the index. A very small page-size (64 is
the minimum) will be less efficient, but can be used to stress the
BTree-code during testing.
binlog_gtid_index_span_min (default 65536)
Control sparseness of the binlog GTID index. If set to N, at most one
index record will be added for every N bytes of binlog file written.
This can be used to reduce the number of records in the index, at
the cost only of having to scan a few more events in the binlog file
before finding the target position
Two status variables are available to monitor the use of the GTID indexes:
Binlog_gtid_index_hit
Binlog_gtid_index_miss
The "hit" status increments for each successful lookup in a GTID index.
The "miss" increments when a lookup is not possible. This indicates that the
index file is missing (eg. binlog written by old server version
without GTID index support), or corrupt.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
Fix that rpl_slave_state::load() was calling rpl_slave_state::update() without
holding LOCK_slave_state.
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
... on semisync slave
To provide semisync master crash-recovery the same server-id transactions
were made to accept for execution on the semisync slave when the strict gtid
mode (see MDEV-27760).
That however caused out-of-order error on a master's transaction
server of the circular setup.
The error was fair in the sense of the gtid strict mode rule as indeed
under the condition of the circular setup the replicated transaction
already exists in the local binlog.
This is fixed by the commit to ignore on the gtid strict mode semisync
slave those gtids that exist in the slave's binlog that effectively restores
the default same-server-id ignore policy.
At the same time the fixes complies with MDEV-21117 semisync slave recovery
to accept the same server-id transactions that do not exist in local binlog.
In cases of a faulty master or an incorrect binlog event producer, that slave is working with,
sends an incomplete group of events slave must react with an error to not to log
into the relay-log any new events that do not belong to the incomplete group.
Fixed with extending received event properties check when slave connects to master
in gtid mode.
Specifically for the event that can be a part of a group its relay-logging is
permitted only when its position within the group is validated.
Otherwise slave IO thread stops with ER_SLAVE_RELAY_LOG_WRITE_FAILURE.
New Feature:
============
Extend mariadb-binlog command-line tool to allow for filtering
events using GTID domain and server ids. The functionality mimics
that of a replica server’s DO_DOMAIN_IDS, IGNORE_DOMAIN_IDS, and
IGNORE_SERVER_IDS from CHANGE MASTER TO. For completeness, this
patch additionally adds the option --do-server-ids as an alias for
--server-id, which now accepts a list of server ids instead of a
single one.
Example usage:
mariadb-binlog --do-domain-ids=2,3,4 --do-server-ids=1,3
master-bin.000001
Functional Notes:
1. --do-domain-ids cannot be combined with --ignore-domain-ids
2. --do-server-ids cannot be combined with --ignore-server-ids
3. A domain id filter can be combined with a server id filter
4. When any new filter options are combined with the
--gtid-strict-mode option, events from excluded domains/servers are
not validated.
5. Domain/server id filters can be combined with GTID ranges (i.e.
specifications of --start-position and --stop-position). However,
because the --stop-position option implicitly undertakes filtering
to only output events within its range of domains, when combined
with --do-domain-ids or --ignore-domain-ids, output will consist of
the intersection between the filters. Specifically, with
--do-domain-ids and --stop-position, only events with domain ids
present in both argument lists will be output. Conversely, with
--ignore-domain-ids and --stop-position, only events with domain ids
present in the --stop-position and absent from the
--ignore-domain-ids options will be output.
Reviewed By
============
Andrei Elkin <andrei.elkin@mariadb.com>
This patch fixes two issues:
First, it fixes test failure due to GTID List events
having inconsistent ordering of domain ids. In
particular, this patch ensures that a GTID list log
event will have its GTIDs ordered by domain id
(ascending) followed by sequence number (ascending).
Second, it fixes an assert which could use an
unintialized variable.
Reviewed By:
============
Andrei Elkin <andrei.elkin@mariadb.com>
New Feature:
===========
This commit extends the mariadb-binlog capabilities to allow events
to be filtered by GTID ranges. More specifically, the
--start-position and --stop-position arguments have been extended to
accept values formatted as a list of GTID positions, e.g.
--start-position=0-1-0,1-2-55. The following specific capabilities
are addressed:
1) GTIDs can be used to filter results on local binlog files
2) GTIDs can be used to filter results from remote servers
3) Implemented --gtid-strict-mode that ensures the GTID event
stream in each domain is monotonically increasing
4) Added new level of verbosity in mysqlbinlog -vvv to print
additional diagnostic information/warnings about invalid GTID
states
5) For a given GTID range, its start and stop position parameters
aim to mimic the behaviors of
CHANGE MASTER TO MASTER_USE_GTID=slave_pos and
START SLAVE UNTIL master_gtid_pos=<GTID>, respectively. In
particular, the start-position list expresses a gtid state of
the server, similarly to how @@global.gtid_slave_pos expresses
the gtid state of a slave server when connecting to a master
with MASTER_USE_GTID=slave_pos.
The GTID start-position list is exclusive and the
stop-position list is inclusive. This allows users to receive
events strictly after those that they already have, and is
useful in cases of point in (logical) time recovery including
1) events were received out of order and should be re-sent, or
2) specifying the gtid state of a slave to get events newer
than their current state. If a seq_no is 0 for start-position,
it means to include the entirety of the domain. If a seq_no is
0 for stop-position, it means to exclude all events from that
domain. The GTIDs provided in a start position argument must
match with the GTID state of the first processed log (i.e.
those listed in the Gtid_list event). If a stop position is
provided, the events that are output are limited to only those
with domain ids listed in the argument. When specifying
combinations of start and stop positions, the following
behaviors are expected:
[--start-position without --stop-position]: Events that have domain
ids in the start position are output if their seq_no occurs after
the respective start position. Events with domain ids that are
unspecified in the start position list are also output. Note that if
the Gtid_list event of the first binary log is populated (i.e.
non-empty), each domain in the Gtid_list must be present in the
start-position list with a seq_no at or after the listed value.
This behavior mimics how a slave only processes events after the
state provided by @@global.gtid_slave_pos when connecting to a
master with CHANGE MASTER TO MASTER_USE_GTID=slave_pos.
[--stop-position without --start-position]: Output is limited to
only events with both 1) domain ids that are present in the given
stop position list and 2) seq_nos that are less than or equal to
their respective stop GTID. Once all GTIDs in the stop position
list have been processed, the program will stop processing log
files. This behavior mimics how
START SLAVE UNTIL master_gtid_pos=<G>
has a slave only process events with domain ids present in G with
their seq_nos at or before the respective gtid.
[--start-position and --stop-position]: Output consists of the
intersection between the events permitted by both the start and stop
position rules. More concretely, the output can be defined by a
union of the following rules:
1. For domains which exist in both the start and stop position
lists, the events which exist in-between these positions
(exclusive start, inclusive stop) are output
2. For all other events, the rules of
[--stop-position without --start-position] are followed
This is due to the implicit filtering within each individual rule.
Even though the start position rule always includes events from
unspecified domains, the stop position rule takes precedence because
it always excludes events from unspecified domains. In other words,
events which the start position rule would have included would then
always be excluded by the stop position rule.
[neither --start-position nor --stop-position]: Events are not
omitted based on GTID positioning; however, --gtid-strict-mode and
-vvv can still analyze gtid correctness for warning and error
reporting.
[repeated specification of --start-position or --stop-position]:
Subsequent specifications of start and stop positions completely
override previous ones. E.g., if invoked as
mysqlbinlog --start-position=<G1> --start-position=<G2> ...
All GTIDs specified in G1 are ignored and only those specified in G2
are used for the start position.
A few additional notes:
1) this commit squashes together the commits:
f4319661120e-78a9d49907ba
2) Changed rpl.rpl_blackhole_row_annotate test because it has
out of order GTIDs in its binlog, so I added
--skip-gtid-strict-mode
3) After all binlog events have been written, the session server
id and domain id are reset to their values in the global state
Reviewed By:
===========
Andrei Elkin: <andrei.elkin@mariadb.com>
This patch changes how old rows in mysql.gtid_slave_pos* tables are deleted.
Instead of doing it as part of every replicated transaction in
record_gtid(), it is done periodically (every @@gtid_cleanup_batch_size
transaction) in the slave background thread.
This removes the deletion step from the replication process in SQL or worker
threads, which could speed up replication with many small transactions. It
also decreases contention on the global mutex LOCK_slave_state. And it
simplifies the logic, eg. when a replicated transaction fails after having
deleted old rows.
With this patch, the deletion of old GTID rows happens asynchroneously and
slightly non-deterministic. Thus the number of old rows in
mysql.gtid_slave_pos can temporarily exceed @@gtid_cleanup_batch_size. But
all old rows will be deleted eventually after sufficiently many new GTIDs
have been replicated.
This would happen especially in optimistic parallel replication, where there
is a good chance that a transaction will be rolled back (due to conflicts)
after it has executed record_gtid(). If the transaction did any deletions of
old rows as part of record_gtid(), those deletions will be undone as well.
And the code did not properly ensure that the deletions would be re-tried.
This patch makes record_gtid() remember the list of deletions done as part
of a transaction. Then in rpl_slave_state::update() when the changes have
been committed, we discard the list. However, in case of error and rollback,
in cleanup_context() we will instead put the list back into
rpl_global_gtid_slave_state so that the deletions will be re-tried later.
Probably fixes part of the cause of MDEV-12147 as well.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>
This was done in, among other things:
- thd->db and thd->db_length
- TABLE_LIST tablename, db, alias and schema_name
- Audit plugin database name
- lex->db
- All db and table names in Alter_table_ctx
- st_select_lex db
Other things:
- Changed a lot of functions to take const LEX_CSTRING* as argument
for db, table_name and alias. See init_one_table() as an example.
- Changed some function arguments from LEX_CSTRING to const LEX_CSTRING
- Changed some lists from LEX_STRING to LEX_CSTRING
- threads_mysql.result changed because process list_db wasn't always
correctly updated
- New append_identifier() function that takes LEX_CSTRING* as arguments
- Added new element tmp_buff to Alter_table_ctx to separate temp name
handling from temporary space
- Ensure we store the length after my_casedn_str() of table/db names
- Removed not used version of rename_table_in_stat_tables()
- Changed Natural_join_column::table_name and db_name() to never return
NULL (used for print)
- thd->get_db() now returns db as a printable string (thd->db.str or "")
As reported in MDEV-11969 "there's no way to ditch knowledge" about some
domain that is no longer updated on a server. Besides being of annoyance to
clutter output in DBA console stale domains can prevent the slave
to connect the master as MDEV-12012 witnesses.
What domain is obsolete must be evaluated by the user (DBA) according
to whether the domain info is still relevant and will the domain ever
receive any update.
This patch introduces a method to discard obsolete gtid domains from
the server binlog state. The removal requires no event group from such
domain present in existing binlog files though. If there are any the
containing logs must be first PURGEd in order for
FLUSH BINARY LOGS DELETE_DOMAIN_ID=(list-of-domains)
succeed. Otherwise the command returns an error.
The list of obsolete domains can be computed through
intersecting two sets - the earliest (first) binlog's Gtid_list
and the current value of @@global.gtid_binlog_state - and extracting
the domain id components from the intersection list items.
The new DELETE_DOMAIN_ID featured FLUSH continues to rotate binlog
omitting the deleted domains from the active binlog file's Gtid_list.
Notice though when the command is ineffective - that none of requested to delete
domain exists in the binlog state - rotation does not occur.
Obsolete domain deletion is not harmful for connected slaves as long
as master side binlog files *purge* is synchronized with FLUSH-DELETE_DOMAIN_ID.
The slaves must have the last event from purged files processed as usual,
in order not to bump later into requesting a gtid from a file which
was already gone.
While the command is not replicated (as ordinary FLUSH BINLOG LOGS is)
slaves, even though having extra domains, won't suffer from reconnection errors
thanks to master-slave gtid connection protocol allowing the master
to be ignorant about a gtid domain.
Should at failover such slave to be promoted into master role it may run
the ex-master's
FLUSH BINARY LOGS DELETE_DOMAIN_ID=(list-of-domains)
to clean its own binlog state.
NOTES.
suite/perfschema/r/start_server_low_digest.result
is re-recorded as consequence of internal parser codes changes.
Intermediate commit.
Fix compilation failure with different my_atomic implementation.
The my_atomic_loadptr* takes void ** as first argument, so variables
updated with it needs to be void * (it is not legal C to cast
some_type ** to void **).
Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)
Changes:
- This caused some ABI changes
- lex_string_set now uses LEX_CSTRING
- Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
code
- Added item_empty_name and item_used_name to be able to distingush between
items that was given an empty name and items that was not given a name
This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
give the error.
TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
(as part of lower_case_table_names)
Intermediate commit.
Fix incorrect assertion. The hton in the list of pending GTIDs can be
NULL, in the special case where we failed to load the
mysql.gtid_slave_pos table at server startup, but nevertheless allow
non-GTID replication to proceed.
Intermediate commit.
Implement auto-creation of mysql.gtid_slave_pos* tables with needed engines,
if listed in --gtid-pos-auto-engines.
Uses an asynchronous approach to minimise locking overhead.
The list of available tables is extended with a flag. Extra entries are
added for --gtid-pos-auto-engines tables that do not exist yet, marked as
not existing but ready for auto-creation.
If record_gtid() needs a table marked for auto-creation, it sends a request
to the slave background thread to create the table, and continues to use an
existing table for the current and immediately coming transactions.
As soon as the slave background thread has made the new table available, it
will be used for all subsequent relevant transactions in record_gtid().
This asynchronous approach also avoids a lot of complex issues around trying
to do DDL in the middle of an on-going transaction.
Intermediate commit.
This commit implements that record_gtid() selects a gtid_slave_posXXX table
with a storage engine already in use by current transaction, if any.
The default table mysql.gtid_slave_pos is used if no match can be found on
storage engine, or for GTID position updates with no specific storage
engine.
Table discovery of mysql.gtid_slave_pos* happens on initial GTID state load
as well as on every START SLAVE. Some effort is made to make this possible
without additional locking. New tables are added using lock-free atomics.
Removing tables requires stopping all slaves first. A warning is given in
the error log when a table is removed but a non-stopped slave still has a
reference to it.
If multiple mysql.gtid_slave_posXXX tables with same storage engine exist,
one is chosen arbitrarily to be used, with a warning in the error log. GTID
data from all tables is still read, but only one among redundant tables with
same storage engine will be updated.
Intermediate commit.
For each GTID recorded in mysq.gtid_slave_pos, keep track of which
engine the update was made in.
This will be later used to know which rows can be deleted in the table
of a given engine.
Intermediate commit.
Keep track of which mysql.gtid_slave_posXXX tables are available for each
engine, by searching for all tables in the mysql schema with names that
start with "gtid_slave_pos".
The list is computed at server start when the GTID position is loaded, and
it is re-computed on every START SLAVE command. This way, the DBA can
manually add a table for a new engine, and it will be automatically picked
up on next START SLAVE, so a full server restart is not needed.
The list is not yet actually used in the code.
- Change some static variables to dynamic to ensure that we don't do any memory
allocations before server starts or stops
- Print more memory information on SIGHUP. Fixed output.
- Write out if memory was lost if run with --debug-at-exit
- Fixed wrong #ifdef in sql_cache.cc
This includes fixing all utilities to not have any memory leaks,
as safemalloc warnings stopped tests from passing on MacOSX.
- Ensure that all clients takes character-set-dir, as the
libmysqlclient library will use it.
- mysql-test-run now passes character-set-dir to all external clients.
- Changed dynstr_free() so that it can be called twice (made freeing code easier)
- Changed rpl_global_gtid_slave_state to be allocated dynamicly as it
includes a mutex that needs to be initizlied/destroyed before my_end() is called.
- Removed rpl_slave_state::init() and rpl_slave_stage::deinit() as
their job are better handling by constructor and delete.
- Print alias instead of table_name in check_duplicate_key as
table_name may have been converted to lower case.
Other things:
- Fixed a case in time_to_datetime_with_warn() where we where
using && instead of & in tests
