The offending query returns a wrong result set because the optimizer
erroneously eliminated the where condition evaluated it to TRUE.
The cause of this wrong transformation was that the flag maybe_null
for an inner table of the outer join was not set to TRUE after the
table had replaced the wrapping view.
Now the function SELECT_LEX::update_used_tables resets the value
of the maybe_null flag for each leaf table of the query after all
merges of views have been done.
The function generate_derived_keys_for_table incorrectly handled
the cases when a materialized view or derived table could be accessed
by different keys on the same fields if these keys depended on the
same tables.
The bug lp:798213 exposes a design flaw in --innodb-release-locks-early.
It does not work with InnoDB crash recovery, so it breaks transactional
integrety. So remove the feature.
semijoin=on,firstmatch=on,loosescan=on
to
semijoin=off,firstmatch=off,loosescan=off
Adjust the testcases:
- Modify subselect*.test and join_cache.test so that all tests
use the same execution paths as before (i.e. optimizations that
are being tested are enabled)
- Let all other test files run with the new default settings (i.e.
with new optimizations disabled)
- Copy subquery testcases from these files into t/subselect_extra.test
which will run them with new optimizations enabled.
Analysis:
This bug consists of two related problems that are
result of too early evaluation of single-row subqueries
during the optimization phase of the outer query.
Several optimizer code paths try to evaluate single-row
subqueries in order to produce a constant and use that
constant for further optimzation.
When the execution of the subquery peforms destructive
changes to the representation of the subquery, and these
changes are not anticipated by the subsequent optimization
phases of the outer query, we tipically get a crash or
failed assert.
Specifically, in this bug the inner-most suqbuery with
DISTINCT triggers a substitution of the original JOIN
object by a single-table JOIN object with a temp table
needed to perform the DISTINCT operation (created by
JOIN::make_simple_join).
This substitution breaks EXPLAIN because:
a) in the first example JOIN::cleanup no longer can
reach the original table of the innermost subquery, and
close all indexes, and
b) in this second test query, EXPLAIN attempts to print
the name of the internal temp table, and crashes because
the temp table has no name (NULL pointer instead).
Solution:
a) fully disable subquery evaluation during optimization
in all cases - both for constant propagation and range
optimization, and
b) change JOIN::join_free() to perform cleanup irrespective
of EXPLAIN or not.
- Fixed multi-user problem with one thread doing inserts and another doing scans that gave error 175
- Fixed bug that caused assert in move_to_next_bitmap() & _ma_read_bitmap_page()
- Much more DBUG_ASSERT(!maria_assert_if_crashed_table) to detect errors early
- EXTERNAL_LOCKING -> MARIA_EXTERNAL_LOCKING (to use same define everywhere
storage/maria/ma_bitmap.c:
More secure handling of first_bitmap_with_space (now we also take care of wrong values)
Don't set page to -1; This fixed unlikely bug that caused assert in move_to_next_bitmap() & _ma_read_bitmap_page()
storage/maria/ma_blockrec.c:
More DBUG_ASSERT()'s
Fixed multi-user problem with one thread doing inserts and another doing scans that gave error 175
(We should use data_file_length from start of scan, not new value as new bitmap page may not yet be in page cache)
storage/maria/ma_check.c:
EXTERNAL_LOCKING -> MARIA_EXTERNAL_LOCKING (to use same define everywhere)
storage/maria/ma_checkpoint.c:
Made maria_checkpoint_min_activity static so that one can change it in debugger while testing.
Fixed long standing performance problem that caused write of state info at checkpoint for any file that was ever changed since open.
storage/maria/ma_create.c:
EXTERNAL_LOCKING -> MARIA_EXTERNAL_LOCKING (to use same define everywhere
storage/maria/ma_dynrec.c:
Added missing MARIA_EXTERNAL_LOCKING (minor performance improvement)
storage/maria/ma_locking.c:
EXTERNAL_LOCKING -> MARIA_EXTERNAL_LOCKING (to use same define everywhere
storage/maria/ma_open.c:
EXTERNAL_LOCKING -> MARIA_EXTERNAL_LOCKING (to use same define everywhere
storage/maria/ma_pagecache.c:
Added assert to detect reads outside of data file
storage/maria/maria_def.h:
Added checkpoint_state to cache state writes in checkpoint
The assert conditions in the functions Item_direct_ref_to_ident::transform
and Item_direct_ref_to_ident::compile could be not valid after constant
propagation when fields and field references may be substituted for constants.
Not only these invalid asserts have been removed, but the functions containing
them have been removed as well because now Item_ref::transform and
Item_ref::compile can be used instead of them.
include/Makefile.am:
Added missing \
mysql-test/mysql-test-run.pl:
Suppress warning when ha_archive is not compiled
mysql-test/r/variables-big.result:
Updated results
- The client gets a progress report message that triggers a callback function if requested with mysql_options(MYSQL_PROGRESS_CALLBACK, function)
- Added Progress field last to 'show processlist'
- Stage, Max_stage and Progress field added to information_schema.progresslist
- The 'mysql' client by defaults enables progress reports when the output is a tty.
- Added progress_report_time time variable to configure how often progress reports is sent to client
Added read only system variable 'in_transaction' which is 1 if we have executed a BEGIN statement.
client/client_priv.h:
Added OPT_REPORT_PROGRESS
client/mysql.cc:
Added option --progress-reports (on by default if not batch mode)
Progress reports is written to stdout for long running commands
include/Makefile.am:
Added mysql/service_progress_report.h
include/myisamchk.h:
Added variables to be able to do progress reporting in Aria and later in MyISAM
include/mysql.h:
Added new mysql_options() parameter: MYSQL_PROGRESS_CALLBACK
include/mysql.h.pp:
Added new mysql_options() parameter: MYSQL_PROGRESS_CALLBACK
include/mysql/plugin.h:
Added functions for reporting progress.
include/mysql/plugin_auth.h.pp:
Added functions for reporting progress.
include/mysql_com.h:
Added CLIENT_PROGRESS mysql_real_connect() flag.
include/sql_common.h:
Added callback function for reporting progress
mysql-test/r/old-mode.result:
Ensure that SHOW PROGRESSLIST doesn't have the Progress column in old mode.
mysql-test/suite/funcs_1/datadict/datadict_priv.inc:
Added new column
mysql-test/suite/funcs_1/datadict/processlist_priv.inc:
Test all new PROCESSLIST columns
mysql-test/suite/funcs_1/r/is_columns_is.result:
Updated results
mysql-test/suite/funcs_1/r/is_columns_is_embedded.result:
Updated results
mysql-test/suite/funcs_1/r/is_columns_mysql_embedded.result:
Updated results
mysql-test/suite/funcs_1/r/is_tables_is_embedded.result:
Updated results
mysql-test/suite/funcs_1/r/processlist_priv_no_prot.result:
Updated results
mysql-test/suite/funcs_1/r/processlist_priv_ps.result:
Updated results
mysql-test/suite/funcs_1/r/processlist_val_no_prot.result:
Updated results
mysql-test/suite/funcs_1/r/processlist_val_ps.result:
Updated results
mysql-test/suite/pbxt/r/pbxt_locking.result:
Updated results
mysql-test/suite/pbxt/r/skip_name_resolve.result:
Updated results
mysql-test/t/old-mode.test:
Ensure that SHOW PROGRESSLIST doesn't have the Progress column in old mode.
plugin/handler_socket/handlersocket/Makefile.am:
Added -lmysqlservices
scripts/mytop.sh:
Made 'State' field width dynamic.
Added 'Progress' to process list display.
sql-common/client.c:
Added handling of progress messages.
Removed check_license() function.
sql/mysql_priv.h:
Added opt_progress_report_time
sql/mysqld.cc:
Added progress_report_time time variable to configure how often progress reports is sent to client
sql/protocol.cc:
Added net_send_progress_packet()
sql/protocol.h:
New prototypes
sql/set_var.cc:
Added variables progress_report_time and in_transaction
sql/sql_acl.cc:
Safety fix: Made client_capabilities ulonglong
sql/sql_class.cc:
Added interface functions for progress reporting
sql/sql_class.h:
Added varibles in THD for progress reporting.
Added CF_REPORT_PROGRESS
sql/sql_load.cc:
Added progress reporting for LOAD DATA INFILE
sql/sql_parse.cc:
Added CF_REPORT_PROGRESS for top level commands for which it's safe to send progress reports to client
sql/sql_show.cc:
Added Progress field last to 'show processlist'
Stage, Max_stage and Progress field added to information_schema.progresslist
sql/sql_table.cc:
Added progress reporting for ALTER TABLE
Added THD as argument to copy_data_between_tables()
storage/maria/ha_maria.cc:
Added progress reporting for check table, repair table, analyze table
Fixed a bug in start_bulk_insert() that caused alter table to always run with all keys enabled.
storage/maria/ma_check.c:
Added progress reporting
Remember old state before starting repair. This removes some warnings from optimize_table if create-with-sort fails.
storage/maria/ma_check_standalone.h:
Added dummy reporting function for standalone Aria programs.
storage/maria/ma_sort.c:
Added progress reporting
storage/maria/maria_chk.c:
Updated version
storage/maria/maria_def.h:
Added new prototypes
tests/mysql_client_test.c:
Added test case for progress reporting
The function generate_derived_keys_for_table should set the value of
the number of keys for the derived table to 0 before it starts
generating key definitions for the table. It's important as the
function can be called twice by the optimizer for a derived table
if the query contains a subquery to which the IN-EXIST transformation
is applicable.
Fixed a valgrind complain.
- JOIN::prepare would have set JOIN::table_count to incorrect value (bad merge of MWL 106)
- optimize_keyuse() would use table-bit as table number
(the change in optimize_keyuse is also the reason for query plan changes. Not
expected to have much effect because only handles cases of no index statistics)
- st_select_lex::register_dependency_item() ignored the fact that some of the
selects on the dependency paths could have been merged to their parents (because they
were mergeable VIEWs)
- Undo the incorrect fix in Item_subselect::recalc_used_tables(): do not call
fix_after_pullout() for Item_subselect::Ref_to_outside members.
If the expression for a derived table contained a clause LIMIT 0
SELECT from such derived table incorrectly returned a non-empty set.
Fixed by ensuring JOIN::do_send_rows to be updated after the call
of st_select_lex_unit::set_limit that sets the value of
JOIN::unit->select_limit_cnt.
Due to this bug in the function generate_derived_keys_for_table some
key definitions to access materialized derived tables or materialized
views were constructed with invalid info for their key parts.
This could make the server crash when it optimized queries using
materialized derived tables or materialized views.
- Fixed performance bug in alter table with Aria; Aria didn't use disable keys + enable keys
- Fixed wrong warning about 'Wrong CRC on datapage' from REPAIR TABLE with aria block tables.
- Fixed bug in aria_chk that disabled performance counters.
- Added --translog_buffer_size to maria_read_log.
storage/maria/ha_maria.cc:
Fixed performance bug in alter table with Aria; Aria didn't use disable keys + enable keys
storage/maria/ma_bitmap.c:
Added some DBUG_ASSERT()'s and made code more uniform
storage/maria/ma_check.c:
Fixed wrong warning about 'Wrong CRC on datapage' from REPAIR TABLE with aria block tables.
storage/maria/ma_pagecache.c:
Copy read pages to buffer even if there was an error (to be able to detect zero filled pages)
storage/maria/maria_chk.c:
Fixed bug in aria_chk that disabled performance counters.
storage/maria/maria_read_log.c:
Added option to set translog_buffer_size
- The crash was because a NOT NULL table column inside the subquery was considered NULLable
because the code thought it was on the inner side of an outer join nest.
- Fixed by making correct distinction between tables inside outer join nests and inside semi-join nests.
This crashing bug could manifest itself at execution of join queries
over materialized derived tables with IN subquery predicates in the
where clause. If for such a query the optimizer chose to use duplicate
weed-out with duplicates in a materialized derived table and chose to
employ join cache the the execution could cause a crash of the server.
It happened because the JOIN_CACHE::init method assumed that the value
of TABLE::file::ref is set at the moment when the method was called
for the employed join cache. It's true for regular tables, but it's
not true for materialized derived tables that are filled now at the
first access to them, i.e. after the JOIN_CACHE::init has done its job.
To fix this problem for any ROWID field of materialized derived table
the procedure that copies fields from record buffers into the employed
join buffer first checks whether the value of TABLE::file::ref has
been set for the table, and if it's not so the procedure sets this value.
- Update test results
- Fix a problem with PS:
= convert_subq_to_sj() should not save where to prep_where or on_expr to prep_on_expr.
= After an unmerged subquery predicate has been pulled, it should call fix_after_pullout() for
outer_refs.
Analysis:
The failed assert ensured that the choice of subquery strategy
is performed only for queries with at least one table. If there
is a LIMIT 0 clause all tables are removed, and the subquery is
neither optimized, nor executed during actual optimization. However,
if the query is EXPLAIN-ed, the EXPLAIN execution path doesn't remove
the query tables if there is a LIMIT 0 clause. As a result, the
subquery optimization code is called, which violates the ASSERT
condition.
Solution:
Transform the assert into a condition, and if the outer query
has no tables assume that there will be at most one subquery
execution.
There is potentially a better solution by reengineering the
EXPLAIN/optimize code, so that subquery optimization is not
done if not needed. Such a solution would be a lot bigger and
more complex than a bug fix.
scripts/CMakeLists.txt:
Added mytop
scripts/Makefile.am:
Added mytop
scripts/make_binary_distribution.sh:
Added mytop
scripts/make_win_bin_dist:
Added mytop
scripts/mytop.sh:
Added mytop (with some small trivial changes to make it workg good also for MariaDB)
support-files/mysql.spec.sh:
Added mytop
