In 3b662c6ebd, it was discovered that the
values of the 'wsrep_is_on' and 'wsrep_cannot_replicate_tz' variables need
to be overridden for embedded builds to pass
However, there are other build configurations where these variables also
have NULL values. The mariadb-tzinfo-to-sql script (implemented in
sql/tztime.cc) can be slightly modified to set its 'wsrep_is_on' and
'wsrep_cannot_replicate_tz' variables more predictably in all such cases,
thus allowing the mysql_tzinfo_to_sql_symlink.test test to pass without
any special-casing for particular build types.
See comments:
- 3b662c6ebd (r78994411)
- https://jira.mariadb.org/browse/MDEV-28782?focusedCommentId=230038&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-230038
All new code of the whole pull request, including one or several files that
are either new files or modified ones, are contributed under the BSD-new
license. I am contributing on behalf of my employer Amazon Web Services,
Inc.
This bug could cause a crash of the server when executing queries containing
ANY/ALL predicands with redundant subqueries in GROUP BY clauses.
These subqueries are eliminated by remove_redundant_subquery_clause()
together with elimination of GROUP BY list containing these subqueries.
However the references to the elements of the GROUP BY remained in the
JOIN::all_fields list of the right operand of of the ALL/ANY predicand.
Later these references confused make_aggr_tables_info() when forming
proper execution structures after ALL/ANY predicands had been replaced
with expressions containing MIN/MAX set functions.
The patch just removes these references from JOIN::all_fields list used
by the subquery of the ALL/ANY predicand when its GROUP BY clause is
eliminated.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
Part #2: Extend heuristic pruning to use multiple tables as the
"Model tables".
Before the patch, heuristic pruning uses only one "Model table":
The table which had the best cost AND record became the "Model table".
After that, if a table's cost and record were both worse than
those of the Model Table, the table would be pruned away.
This didn't work well when the first table (the optimizer sorts them
by record_count) had low record_count but relatively high cost: nothing
could be pruned afterwards.
The patch adds the two additional "Model tables": one with the least
cost and the other with the least record_count.
(In both cases, a table can be pruned away if BOTH its cost and
record_count are worse than those of a Model table)
The new pruning is active when the number of tables to consider for
the prefix is higher than @@optimizer_extra_pruning_depth.
One can see the new pruning in the Optimizer Trace as
- "pruned_by_heuristic":"min_record_count", or
- "pruned_by_heuristic":"min_read_time".
Old heuristic pruning shows as "pruned_by_heuristic":1.
SELECT_LEX::first_select()->join is NULL for degenerate derived tables
which are known to have just one row and so were already materialized
by the optimizer.
This commit adds a check for this.
Elimination of unnecessary tables from SQL queries is already present
in MariaDB. But it only works for regular tables and not for derived ones.
Imagine we have a view:
CREATE VIEW v1 AS SELECT a, b, max(c) AS maxc FROM t1 GROUP BY a, b
Due to "GROUP BY a, b" the values of combinations {a, b} are unique,
and this fact can be treated as like derived table "v1" has a unique key
on fields {a, b}.
Suppose we have a SQL query:
SELECT t2.* FROM t2 LEFT JOIN v1 ON t2.a=v1.a and t2.b=v1.b
1. Since {v1.a, v1.b} is unique and both these fields are bound to t2,
"v1" is functionally dependent on t2.
This means every record of "t2" will be either joined with
a single record of "v1" or NULL-complemented.
2. No fields of "v1" are present on the SELECT list
These two facts allow the server to completely exclude (eliminate)
the derived table "v1" from the query.
MDEV-28073 Slow query performance in MariaDB when using many table
The idea is to prefer and chain EQ_REF tables (tables that uses an
unique key to find a row) when searching for the best table combination.
This significantly reduces row combinations that has to be examined.
This is optimization is enabled when setting optimizer_prune_level=2
(which is now default).
Implementation:
- optimizer_prune_level has a new level, 2, which enables EQ_REF
optimization in addition to the pruning done by level 1.
Level 2 is now default.
- Added JOIN::eq_ref_tables that contains bits of tables that could use
potentially use EQ_REF access in the query. This is calculated
in sort_and_filter_keyuse()
Under optimizer_prune_level=2:
- When the greedy_optimizer notices that the preceding table was an
EQ_REF table, it tries to add an EQ_REF table next. If an EQ_REF
table exists, only this one will be considered at this level.
We also collect all EQ_REF tables chained by the next levels and these
are ignored on the starting level as we have already examined these.
If no EQ_REF table exists, we continue as normal.
This optimization speeds up the greedy_optimizer combination test with
~25%
Other things:
- I ported the changes in MySQL 5.7 to greedy_optimizer.test to MariaDB
to be able to ensure we can handle all cases that MySQL can do.
- I have run all tests with --mysqld=--optimizer_prune_level=1 to verify that
there where no test changes.
MDEV-28073 Slow query performance in MariaDB when using many tables
The faster we can find a good query plan, the more options we have for
finding and pruning (ignoring) bad plans.
This patch adds sorting of plans to best_extension_by_limited_search().
The plans, from best_access_path() are sorted according to the numbers
of found rows. This allows us to faster find 'good tables' and we are
thus able to eliminate 'bad plans' faster.
One side effect of this patch is that if two tables have equal cost,
the table that which was used earlier in the query is preferred.
This allows users to improve plans by reordering eq_ref tables in the
order they would like them to be uses.
Result changes caused by the patch:
- Traces are different as now we print the cost for using tables before
we start considering them in the plan.
- Table order are changed for some plans. In most cases this is because
the plans are equal and tables are in this case sorted according to
their usage in the original query.
- A few plans was changed as the optimizer was able to find a better
plan (that was pruned by the original code).
Other things:
- Added a new statistic variable: "optimizer_join_prefixes_check_calls",
which counts number of calls to best_extension_by_limited_search().
This can be used to check the prune efficiency in greedy_search().
- Added variable "JOIN_TAB::embedded_dependent" to be able to handle
XX IN (SELECT..) in the greedy_optimizer. The idea is that we
should prune a table if any of the tables in embedded_dependent is
not yet read.
- When using many tables in a query, there will be some additional
memory usage as we need to pre-allocate table of
table_count*table_count*sizeof(POSITION) objects (POSITION is 312
bytes for now) to hold the pre-calculated best_access_path()
information. This memory usage is offset by the expected
performance improvement when using many tables in a query.
- Removed the code from an earlier patch to keep the table order in
join->best_ref in the original order. This is not needed anymore as we
are now sorting the tables for each best_extension_by_limited_search()
call.
... 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.
It will go into 10.11.
Author: Luis Eduardo Oliveira Lizardo <108760288+mariadb-LuisLizardo@users.noreply.github.com>
Date: Mon Jul 18 17:48:01 2022 +0200
MDEV-28926 Add time spent on query optimizer to JSON ANALYZE (#2193)
* Add query optimizer timer to ANALYZE FORMAT=JSON
* Adapt tests and results
* Change logic to always close the writer after printing query blocks
This commit is a fixup for MDEV-28762
Analysis: Some recursive json functions dont check for stack control
Fix: Add check_stack_overrun(). The last argument is NULL because it is not
used
This avoids LF->CRLF conversion by the C runtime, which historically has
been rather buggy (see MDEV-9409)
Disabling text mode also fixes the --binary-mode in command line client
to work the same on Windows, as it does elsewhere.
The user-visible effect is that some text files, e.g output of mysqldump
or mysqlbinlog will not have CRLF end-of-lines,but LF. That should be
acceptable, as even Notepad can read this Unix EOLs since 2018
(on older Windows, Wordpad can)
Leave error log in text(CRLF) mode for now, for the sake of old Windows.
Not the SPIDER issue - happens to INSERT DELAYED.
the field::make_new_field does't copy the LONG_UNIQUE_HASH_FIELD
flag to the new field. Though the Delayed_insert::get_local_table
copies the field->vcol_info for this field. Ad a result
the parse_vcol_defs doesn't create the expression for that column
so the field->vcol_info->expr is NULL. Which leads to crash.
Backported fix for this from 10.5 - the flagg added in the
Delayed_insert::get_local_table.
Another problem with the USING HASH key is thst the
parse_vcol_defs modifies the table->keys content. Then the same
parse_vcol_defs is called on the table copy that has keys already
modified. Backported fix for that from 10.5 - key copying added
tot the Delayed_insert::get_local_table.
Finally - the created copy has to clear the expr_arena as
this table is not in the thd->open_tables list so won't be
cleared automatically.
1. For INSERT..SELECT statements: don't include table/view the data
is inserted into in the list of leaf tables
2. Remove duplicated and dead code related to table_count
This bug caused crashes when the server executed such a CREATE VIEW
statement whose view specification contained a reference to an unknown
column in a subquery used in ON condition.
The cause of this bug is quite similar to the cause of the bug MDEV-26412.
The fix of this bug is quite similar to the fix for MDEV-26412.
Approved by Sergey Petrunia <sergey@mariadb.com>
MDEV-28567 counted two execution sequences, there is third one which
executes ALTER VIEW before f() is created.
The more appropriate place for this test case is lock_sync.test
Running some statements that use IN subqueries outside context of a regular
query could result in server abnormal termination.
The reason for failure is that internal structures SELECT_LEX/SELECT_LEX_UNIT
created on behalf of parsed query were initialized incorrectly. Incorrect
initialization of the structures SELECT_LEX/SELECT_LEX_UNIT was introduced
by the commit de745ecf29
(MDEV-11953: support of brackets in UNION/EXCEPT/INTERSECT operations)
pushed into 10.4, that is the reason this bug report is not reproduced in 10.3.
To fix the issue the method SLECTE_LEX::register_unit is used for proper
initialization of the data structures SELECT_LEX/SELECT_LEX_UNIT. Additionally,
the method SELECT_LEX::get_slave() was removed from the source code base
since for those use cases where it is used it can be replaced by the method
first_inner_unit().
The incorrect type of mysql.column_stats caused the server during the
upgrade of every other table to complain:
[ERROR] Incorrect definition of table mysql.column_stats: expected column 'hist_type' at position 9
and expected column 'histogram' at position 10 to have type longblob.
To prevent these verbose server errors, we upgrade the
mysql.column_stats table first.
Consequently limit "Incorrect definition of table mysql.*" to the appropriate
set of limited test cases.
The rpl_gtid_errorhandling.result changes the GTID number by one
because of the added early suppression (adding a table row).
Reviewer: Vicențiu Ciorbaru
FixesMariaDB/mariadb-docker#438
Fix the side effect of MDEV-4750 (reenabling innodb_stats_persistent),
so that sporadic MDL acquisition for this table does not interfere with
SELECT from information_schema.metadata_lock_info
optimize_semi_joins() calls update_sj_state() to update semi-join
optimization state in the JOIN class.
greedy_search() algorithm considers different join prefixes,
and then picks one table to put into the join prefix.
Most of the semi-join optimization state is in the table's entry
in the join->positions[cur_prefix_size].
However, it also needs to call update_sj_state() to update the
semi-join optimization state in the JOIN class.
There is one exception, which is the cause of this bug: when we're
inside optimize_semi_join_nests() and are optimizing a subquery,
optimize_semi_joins() does nothing, it doesn't call update_sj_state().
greedy_search() must not do that either.
Depending on OpenSSL version, and at least in 3.0.3, the client-side socket
timeout is reported as generic error (SSL_ERROR_SYSCALL), losing further
details (both errno and GetLastError() return 0). This results in client
reporting "Unknown OpenSSL error" 2026, instead of another generic
"Lost connection to server during query" 2013
Adjusted test case.
Part of MDEV-29000
Summary of changes
- MD_CTX_SIZE is increased
- EVP_CIPHER_CTX_buf_noconst(ctx) does not work anymore, points
to nobody knows where. The assumption made previously was that
(since the function does not seem to be documented)
was that it points to the last partial source block.
Add own partial block buffer for NOPAD encryption instead
- SECLEVEL in CipherString in openssl.cnf
had been downgraded to 0, from 1, to make TLSv1.0 and TLSv1.1 possible
(according to https://github.com/openssl/openssl/blob/openssl-3.0.0/NEWS.md
even though the manual for SSL_CTX_get_security_level claims that it
should not be necessary)
- Workaround Ssl_cipher_list issue, it now returns TLSv1.3 ciphers,
in addition to what was set in --ssl-cipher
- ctx_buf buffer now must be aligned to 16 bytes with openssl(
previously with WolfSSL only), ot crashes will happen
- updated aes-t , to be better debuggable
using function, rather than a huge multiline macro
added test that does "nopad" encryption piece-wise, to test
replacement of EVP_CIPHER_CTX_buf_noconst
part of MDEV-29000
