June 2017 - developers - lists.mariadb.org

[Maria-developers] MDEV-10306 Wrong results with combination of CONCAT, SUBSTR and CONVERT in subquery
by Alexander Barkov 16 Jun '17

16 Jun '17

Hello Sergei, Please review a fix for MDEV-10306. Thanks!

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Re: [Maria-developers] [Commits] 01b2bb79bb78e42108e32af02f1418a660ca861d Fixed the bug mdev-13064.
by Oleksandr Byelkin 16 Jun '17

16 Jun '17

Hi, Igor! Am 15.06.2017 um 23:43 schrieb Igor Babaev: > commit 01b2bb79bb78e42108e32af02f1418a660ca861d > Author: Igor Babaev <igor(a)askmonty.org> > Commit: Igor Babaev <igor(a)askmonty.org> > > Fixed the bug mdev-13064. > > This is another attempt to fix the bug mdev-12992. > This patch introduces st_select_lex::context_analysis_place for > the place in SELECT where context analysis is currently performed. > It's similar to st_select_lex::parsing_place, but it is used at It is OK to push. > the preparation stage. > --- > mysql-test/r/func_group.result | 9 +++++++++ > mysql-test/t/func_group.test | 13 +++++++++++++ > sql/item.cc | 5 ++--- > sql/item_windowfunc.cc | 2 +- > sql/sql_lex.h | 1 + > sql/sql_select.cc | 33 ++++++++++++++++++--------------- > 6 files changed, 44 insertions(+), 19 deletions(-) > > diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result > index cb97ea2..c4e991e 100644 > --- a/mysql-test/r/func_group.result > +++ b/mysql-test/r/func_group.result > @@ -2447,3 +2447,12 @@ DROP TABLE t1; > # > # End of 10.1 tests > # > +# > +# MDEV-13064: assertion `n < m_size' fails in Item::split_sum_func2() > +# > +create table t1 (i int) engine=MyISAM; > +insert into t1 value (1),(2); > +select count(*)+sleep(0) from t1; > +count(*)+sleep(0) > +2 > +drop table t1; > diff --git a/mysql-test/t/func_group.test b/mysql-test/t/func_group.test > index 1e75099..8bbc9e6 100644 > --- a/mysql-test/t/func_group.test > +++ b/mysql-test/t/func_group.test > @@ -1691,3 +1691,16 @@ DROP TABLE t1; > --echo # > --echo # End of 10.1 tests > --echo # > + > +--echo # > +--echo # MDEV-13064: assertion `n < m_size' fails in Item::split_sum_func2() > +--echo # > + > +create table t1 (i int) engine=MyISAM; > +insert into t1 value (1),(2); > + > +select count(*)+sleep(0) from t1; > + > +drop table t1; > + > + > diff --git a/sql/item.cc b/sql/item.cc > index 8db5cfc..df615b5 100644 > --- a/sql/item.cc > +++ b/sql/item.cc > @@ -490,8 +490,7 @@ int Item::save_str_value_in_field(Field *field, String *result) > command => we should check thd->lex->current_select on zero (thd->lex > can be uninitialised) > */ > - if (thd->lex->current_select && > - thd->stmt_arena->is_stmt_prepare_or_first_sp_execute()) > + if (thd->lex->current_select) > { > enum_parsing_place place= > thd->lex->current_select->parsing_place; > @@ -5513,7 +5512,7 @@ bool Item_field::fix_fields(THD *thd, Item **reference) > > SELECT_LEX *select= thd->lex->current_select; > thd->change_item_tree(reference, > - select->parsing_place == IN_GROUP_BY && > + select->context_analysis_place == IN_GROUP_BY && > alias_name_used ? *rf->ref : rf); > > /* > diff --git a/sql/item_windowfunc.cc b/sql/item_windowfunc.cc > index 59a22c6..27b0072 100644 > --- a/sql/item_windowfunc.cc > +++ b/sql/item_windowfunc.cc > @@ -71,7 +71,7 @@ > { > DBUG_ASSERT(fixed == 0); > > - enum_parsing_place place= thd->lex->current_select->parsing_place; > + enum_parsing_place place= thd->lex->current_select->context_analysis_place; > > if (!(place == SELECT_LIST || place == IN_ORDER_BY)) > { > diff --git a/sql/sql_lex.h b/sql/sql_lex.h > index face3bc..0c55ffc 100644 > --- a/sql/sql_lex.h > +++ b/sql/sql_lex.h > @@ -855,6 +855,7 @@ class st_select_lex: public st_select_lex_node > /* reserved for exists 2 in */ > uint select_n_reserved; > enum_parsing_place parsing_place; /* where we are parsing expression */ > + enum_parsing_place context_analysis_place; /* where we are in prepare */ > bool with_sum_func; /* sum function indicator */ > > ulong table_join_options; > diff --git a/sql/sql_select.cc b/sql/sql_select.cc > index 4c64cf2..6c56f01 100644 > --- a/sql/sql_select.cc > +++ b/sql/sql_select.cc > @@ -648,17 +648,15 @@ void remove_redundant_subquery_clauses(st_select_lex *subq_select_lex) > > thd->lex->allow_sum_func|= (nesting_map)1 << select->nest_level; > > - save_place= thd->lex->current_select->parsing_place; > - thd->lex->current_select->parsing_place= IN_ORDER_BY; > + save_place= thd->lex->current_select->context_analysis_place; > + thd->lex->current_select->context_analysis_place= IN_ORDER_BY; > res= res || setup_order(thd, ref_pointer_array, tables, fields, all_fields, > order); > - thd->lex->current_select->parsing_place= save_place; > - thd->lex->allow_sum_func&= ~((nesting_map)1 << select->nest_level); > - save_place= thd->lex->current_select->parsing_place; > - thd->lex->current_select->parsing_place= IN_GROUP_BY; > + thd->lex->allow_sum_func&= ~((nesting_map)1 << select->nest_level); > + thd->lex->current_select->context_analysis_place= IN_GROUP_BY; > res= res || setup_group(thd, ref_pointer_array, tables, fields, all_fields, > group, hidden_group_fields); > - thd->lex->current_select->parsing_place= save_place; > + thd->lex->current_select->context_analysis_place= save_place; > thd->lex->allow_sum_func|= (nesting_map)1 << select->nest_level; > res= res || setup_windows(thd, ref_pointer_array, tables, fields, all_fields, > win_specs, win_funcs); > @@ -712,6 +710,7 @@ void remove_redundant_subquery_clauses(st_select_lex *subq_select_lex) > if (select_lex->handle_derived(thd->lex, DT_PREPARE)) > DBUG_RETURN(1); > > + thd->lex->current_select->context_analysis_place= NO_MATTER; > thd->lex->current_select->is_item_list_lookup= 1; > /* > If we have already executed SELECT, then it have not sense to prevent > @@ -801,12 +800,13 @@ void remove_redundant_subquery_clauses(st_select_lex *subq_select_lex) > > ref_ptrs= ref_ptr_array_slice(0); > > - enum_parsing_place save_place= thd->lex->current_select->parsing_place; > - thd->lex->current_select->parsing_place= SELECT_LIST; > + enum_parsing_place save_place= > + thd->lex->current_select->context_analysis_place; > + thd->lex->current_select->context_analysis_place= SELECT_LIST; > if (setup_fields(thd, ref_ptrs, fields_list, MARK_COLUMNS_READ, > &all_fields, 1)) > DBUG_RETURN(-1); > - thd->lex->current_select->parsing_place= save_place; > + thd->lex->current_select->context_analysis_place= save_place; > > if (setup_without_group(thd, ref_ptrs, tables_list, > select_lex->leaf_tables, fields_list, > @@ -22235,14 +22235,16 @@ int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables, > List<Item> &fields, List<Item> &all_fields, ORDER *order, > bool from_window_spec) > { > - enum_parsing_place parsing_place= thd->lex->current_select->parsing_place; > + enum_parsing_place context_analysis_place= > + thd->lex->current_select->context_analysis_place; > thd->where="order clause"; > for (; order; order=order->next) > { > if (find_order_in_list(thd, ref_pointer_array, tables, order, fields, > all_fields, FALSE, from_window_spec)) > return 1; > - if ((*order->item)->with_window_func && parsing_place != IN_ORDER_BY) > + if ((*order->item)->with_window_func && > + context_analysis_place != IN_ORDER_BY) > { > my_error(ER_WINDOW_FUNCTION_IN_WINDOW_SPEC, MYF(0)); > return 1; > @@ -22284,7 +22286,8 @@ int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables, > List<Item> &fields, List<Item> &all_fields, ORDER *order, > bool *hidden_group_fields, bool from_window_spec) > { > - enum_parsing_place parsing_place= thd->lex->current_select->parsing_place; > + enum_parsing_place context_analysis_place= > + thd->lex->current_select->context_analysis_place; > *hidden_group_fields=0; > ORDER *ord; > > @@ -22300,14 +22303,14 @@ int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables, > all_fields, TRUE, from_window_spec)) > return 1; > (*ord->item)->marker= UNDEF_POS; /* Mark found */ > - if ((*ord->item)->with_sum_func && parsing_place == IN_GROUP_BY) > + if ((*ord->item)->with_sum_func && context_analysis_place == IN_GROUP_BY) > { > my_error(ER_WRONG_GROUP_FIELD, MYF(0), (*ord->item)->full_name()); > return 1; > } > if ((*ord->item)->with_window_func) > { > - if (parsing_place == IN_GROUP_BY) > + if (context_analysis_place == IN_GROUP_BY) > my_error(ER_WRONG_PLACEMENT_OF_WINDOW_FUNCTION, MYF(0)); > else > my_error(ER_WINDOW_FUNCTION_IN_WINDOW_SPEC, MYF(0)); > _______________________________________________ > commits mailing list > commits(a)mariadb.org > https://lists.askmonty.org/cgi-bin/mailman/listinfo/commits

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[Maria-developers] Review for MDEV-12666: CURRENT_ROLE() and DATABASE() does not work in a view
by Alexander Barkov 13 Jun '17

13 Jun '17

Hi Vicentiu, The patch looks fine. Thanks! I have only small comments below: > > [Commits] 974064cde3c: MDEV-12666: CURRENT_ROLE() and DATABASE() does not work in a view > vicentiu vicentiu at mariadb.org > Thu Jun 8 10:11:38 EEST 2017 > > Previous message (by thread): [Commits] 7f2d3c3: MDEV-11084 Select statement with partition selection against MyISAM table opens all partitions. > Next message (by thread): [Commits] d03abc71a49: MDEV-12609: Allow suppression of InnoDB log messages about reserving extents > Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] > > revision-id: 974064cde3c1cd1be9157bc11ce410604807f68b (mariadb-10.0.31-2-g974064cde3c) > parent(s): 54cd5bc703da08be45894495d7f3e2c8117617cd > author: Vicențiu Ciorbaru > committer: Vicențiu Ciorbaru > timestamp: 2017-06-08 10:10:07 +0300 > message: > > MDEV-12666: CURRENT_ROLE() and DATABASE() does not work in a view > > The problem lies in how CURRENT_ROLE is defined. The > Item_func_current_role inherits from Item_func_sysconst, which defines > a safe_charset_converter to be a const_charset_converter. > > During view creation, if there is no role previously set, the current_role() > function returns NULL. > > This is captured on item instantiation and the > const_charset_converter call subsequently returns an Item_null. > In turn, the function is replaced with Item_null and the view is > then created with an Item_null instead of Item_func_current_role. > > Without this patch, the first SHOW CREATE VIEW from the testcase would > have a where clause of WHERE role_name = NULL, while the second SHOW > CREATE VIEW would show a correctly created view. > > The same applies for the DATABASE function, as it can change as well. > > There is an additional problem with CURRENT_ROLE() when used in a > prepared statement. During prepared statement creation we used to set > the string_value of the function to the current role as well as the > null_value flag. During execution, if CURRENT_ROLE was not null, the > null_value flag was never set to not-null during fix_fields. > > Item_func_current_user however can never be NULL so it did not show this > problem in a view before. At the same time, the CURRENT_USER() can not > be changed between prepared statement execution and creation so the > implementation where the value is stored during fix_fields is > sufficient. > > Note also that DATABASE() function behaves differently during prepared > statements. See bug 25843 for details or commit > 7e0ad09edff587dadc3e9855fc81e1b7de8f2199 > <cut> > --- a/sql/item_strfunc.cc > +++ b/sql/item_strfunc.cc > @@ -2344,6 +2344,7 @@ String *Item_func_database::val_str(String *str) > } > else > str->copy(thd->db, thd->db_length, system_charset_info); > + null_value= 0; > return str; > } > > @@ -2378,6 +2379,30 @@ bool Item_func_user::init(const char *user, const char *host) > } > > > +Item *Item_func_sysconst::safe_charset_converter(CHARSET_INFO *tocs) > +{ > + /* > + During view or prepared statement creation, the item should not > + make use of const_charset_converter as it would imply substitution > + with constant items which is not correct. Functions can have different > + values during view creation and view execution based on context. > + > + Return the identical item during view creation and prepare. > + */ > + if (current_thd->lex->context_analysis_only & > + (CONTEXT_ANALYSIS_ONLY_PREPARE | CONTEXT_ANALYSIS_ONLY_VIEW)) > + return this; > + return const_charset_converter(tocs, true, fully_qualified_func_name()); I propose to avoid code duplication and do like this: if (!Item_func_sysconst::const_item()) return this; return return const_charset_converter(tocs, true, fully_qualified_func_name()); > +} > + > +bool Item_func_sysconst::const_item() const > +{ > + if (current_thd->lex->context_analysis_only & > + (CONTEXT_ANALYSIS_ONLY_PREPARE | CONTEXT_ANALYSIS_ONLY_VIEW)) > + return false; > + return true; > +} > + > bool Item_func_user::fix_fields(THD *thd, Item **ref) > { > return (Item_func_sysconst::fix_fields(thd, ref) || > @@ -2403,20 +2428,25 @@ bool Item_func_current_role::fix_fields(THD *thd, Item **ref) > > Security_context *ctx= context->security_ctx > ? context->security_ctx : thd->security_ctx; > - > if (ctx->priv_role[0]) > { > if (str_value.copy(ctx->priv_role, strlen(ctx->priv_role), > system_charset_info)) > return 1; > - > str_value.mark_as_const(); > + null_value= maybe_null= 0; > return 0; > } > null_value= maybe_null= 1; > return 0; > } > > +String* Item_func_current_role::val_str(String * str) > +{ > + DBUG_ASSERT(fixed == 1); > + return null_value ? NULL : &str_value; > +} > + Why did you move val_str() from *.h to *.cc ? The method is just two lines, I'd leave it in *.h <cut>

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[Maria-developers] MDEV-12962 Testing MDEV-10142
by Alexander Barkov 13 Jun '17

13 Jun '17

Hi Andrii, Thanks for looking into this. Please find my comments inline: > > > Below are mostly minor notes for which clarification is needed. > > Conceptual: are we sure that ORACLE mode should invalidate native MariaDB constructs? We need some consistency and in my understanding following should still work in Oracle mode: > ELSE / ELSEIF > % operation (if possible) I'm not sure. Monty, what do you think? > > > 2. MDEV-10343 sql_mode=ORACLE: Providing compatibility for basic SQL data types > > following are valid build-in datatypes declaration in oracle which cause syntax error at the moment (needs to be documented or created another task): > > these probably had to be implemented inside MDEV-10343 > > create or replace table t1(a binary_float); > create or replace table t1(a binary_double); > create or replace table t1(a long raw); > create or replace table t1(a NCLOB); > these need more effort or maybe just must be documented or separate task is needed > create or replace table t1(a varchar(30 byte)); > create or replace table t1(a varchar(30 char)); > create or replace table t1(a timestamp with local time zone); > create or replace table t1(a timestamp with time zone); > create or replace table t1(a interval day); > create or replace table t1(a interval year); > create or replace table t1(a BFILE); > create or replace table t1(a rowid); > create or replace table t1(a urowid(5)); > this should give an error (oracle will return ORA-02017: integer value required ) > MariaDB [test]> create or replace table t1(a number(2.2)); > Query OK, 0 rows affected (0.24 sec) There is a task for TIMESTAMP WITH TIME ZONE: MDEV-10018 Timestamp with time zone For other data types, should we create one task for every data type? > > > 3. MDEV-10411 Providing compatibility for basic PL/SQL constructs > 3.6 Assignment operator > It doesn't sound intuitive that one may write "wait_timeout:=a", but "a:=wait_timeout" shows syntax error. > > begin declare a int; begin a:=wait_timeout; end; end;; One needs to use @ when referring a system variable in the right side: a:=@wait_timeout; It's the same in the default mode: SET wait_timeount=100; but: SET xxx=@wait_timeout; Not sure if we should do anything with that. > > > 3.7 Variable declarations > Oracle allows NOT NULL in variable declaration. Maybe we should allow that syntax as well? > > begin declare a NOT NULL int; begin a:=1; a:=NULL; end; end;; I have created a task for this: MDEV-13078 NOT NULL routine variables > > > 10. MDEV-10585 EXECUTE IMMEDIATE > In ORACLE the command supports 'RETURNING INTO' clause, we should probably document the difference? > > sql_stmt := 'UPDATE emp SET sal = 2000 WHERE empno = :1 > > RETURNING sal INTO :2'; > > EXECUTE IMMEDIATE sql_stmt USING emp_id RETURNING INTO salary; In Oracle, EXECUTE IMMEDIATE also has the "INTO" clause: sql_stmt := 'SELECT * FROM emp WHERE empno = :id'; EXECUTE IMMEDIATE sql_stmt INTO emp_rec USING emp_id; Should we create two new tasks, for RETURNING INTO, and for INTO? > > 12. MDEV-10588 TRUNCATE TABLE t1 DROP|REUSE STORAGE > Following clauses should be allowed in TRUNCATE command as well: > [ PRESERVE MATERIALIZED VIEW LOG | PURGE MATERIALIZED VIEW LOG ] Should we create a task to ignore this syntax? > > 18. MDEV-10577 sql_mode=ORACLE: %TYPE in variable declarations > It is not clear what is expected to happen if table's column definition is altered after stored program creation. Nothing. Data type resolution is done during execution.

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[Maria-developers] Progress report of the Project[Week 2]
by ANKIT KUMAR 12 Jun '17

12 Jun '17

Hi, In this week, I managed to do few contributions and finally completed subtask-1. These are few things that I did this week- 1. Extended CREATE USER syntax- Now there will be multiple authentication mechanisms per user. 2. Created tests for the newly implemented syntax and some tests for previously existing functonalities. Need to give final touch up to the code and will commit tomorrow. Now I will proceed to subtask-2 Week-3[TODO's]- 1. Implement in-memory structures for this new syntax-[Providing it to ACL_USER] 2. Will be able to write data in memory(By the end of Phase-1 evaluation). Kind regards, Ankit Kumar.

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[Maria-developers] libmariadb.so.3 compatibility
by Michal Schorm 08 Jun '17

08 Jun '17

Hello, I'm currently quite confused about the *libmariadb* library. In MariaDB 10.1.24 there are: " libmysqlclient_r.so -> libmysqlclient.so " " libmysqlclient.so -> libmysqlclient.so.18 " " libmysqlclient.so.18 -> libmysqlclient.so.18.0.0 " " libmysqlclient.so.18.0.0 " In MariaDB 10.2.6 there are: " libmariadb.so -> libmariadb.so.3 " In MariaDB-connector-c v2.3.3 there are: " libmysqlclient.so -> libmariadb.so " " libmysqlclient_r.so -> libmariadb.so " " libmariadb.so -> libmariadb.so.2 " " libmariadb.so.2 " -- 1) is "libmariadb.so.2" compatibile with "libmysqlclient.so.18.0.0"? Both API and ABI? 2) is "libmariadb.so.3" compatibile with "libmysqlclient.so.18.0.0"? Both API and ABI? 3) is "libmariadb.so.2" compatibile with "libmariadb.so.3"? Both API and ABI? Many packages in Fedora depends on "libmysqlclient.so". I would like to pack 10.2 to Fedora, but I can't before all those packages move to the libmariadb library. It would be considerably easier transfer for me, if all those libraries were compatibile, so I could provide symlinks (simmilar as in the connector C), and provide time for all those packages in Fedora to move safely. -- Michal Schorm Associate Software Engineer Core Services - Databases Team Red Hat

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Re: [Maria-developers] [Commits] 4d6b16f: Fixed the bug mdev-12838.
by Sergey Petrunia 07 Jun '17

07 Jun '17

Hello Igor, On Wed, May 31, 2017 at 10:45:07AM -0700, IgorBabaev wrote: > revision-id: 4d6b16f10f9991821c128c382d32eb85248b3926 (mariadb-5.5.56-14-g4d6b16f) > parent(s): b8405c853fa30002d164d5fe2b4f8ea8979c09b8 > author: Igor Babaev > committer: Igor Babaev > timestamp: 2017-05-31 10:45:07 -0700 > message: > > Fixed the bug mdev-12838. > ... > +bool JOIN_TAB::keyuse_is_valid_for_access_in_chosen_plan(JOIN *join, > + KEYUSE *keyuse) > +{ > + if (!access_from_tables_is_allowed(keyuse->used_tables, > + join->sjm_lookup_tables)) > + return false; > + if (join->sjm_scan_tables & table->map) > + return true; > + table_map keyuse_sjm_scan_tables= keyuse->used_tables & > + join->sjm_scan_tables; > + if (!keyuse_sjm_scan_tables) > + return true; > + uint sjm_tab_nr= 0; > + while (!(keyuse_sjm_scan_tables & 1 << sjm_tab_nr)) The above "1" is a 32-bit number, while it should have the same bit length as table_map (that is, 64). Please use "table_map(1)". BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog

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[Maria-developers] the Lock on supremum is neccessary ?
by jhx1008 07 Jun '17

07 Jun '17

hi everyone: I use sysbench to do some tests on MySQL 5.7.x, and then I got some problems with the lock added on supremum, I hope someone can give me some advice. my table like this: CREATE TABLE `sbtest1` ( `id` int(11) NOT NULL AUTO_INCREMENT, `k` int(11) NOT NULL DEFAULT '0', `c` char(120) NOT NULL DEFAULT '', `pad` char(60) NOT NULL DEFAULT '', PRIMARY KEY (`id`), ) ENGINE=InnoDB; secondary index is not neccessary, I do not create it!! I have two sessions: session1: begin; select * from sbtest1 where id=123456 for update session2: insert into sbtest1 values(123450, 0,'aaa','bbb'); the records in the table like below: (...),(123440, 264454, xxxxxx, xxxxx), (123456, 251028, xxxxx, xxxxxx),(....) in my opinion, the record with the id=123456 existed, so session1 add the X lock on this record, session2 add the insert intention lock between(123440, 123456), these two locks are not conflicted. session2 will not be blocked by session1. unfortunately, in my case, session2 is blocked by session1, what happens? when session2 is blocked, I do "select * from information_schema.INNODB_LOCKS" use another session, It shows : mysql> select * from information_schema.INNODB_LOCKS; +----------------+-------------+-----------+-----------+------------------+------------+------------+-----------+----------+------------------------+ | lock_id | lock_trx_id | lock_mode | lock_type | lock_table | lock_index | lock_space | lock_page | lock_rec | lock_data | +----------------+-------------+-----------+-----------+------------------+------------+------------+-----------+----------+------------------------+ | 2388:29:2772:1 | 2388 | X | RECORD | `mydb`.`sbtest1` | PRIMARY | 29 | 2772 | 1 | supremum pseudo-record | | 2387:29:2772:1 | 2387 | X | RECORD | `mydb`.`sbtest1` | PRIMARY | 29 | 2772 | 1 | supremum pseudo-record | +----------------+-------------+-----------+-----------+------------------+------------+------------+-----------+----------+------------------------+ both the two sessions want to add X lock on "supremum pseudo-record" in the same time. then I have debugged this instance(row0sel.cc::row_search_mvcc), I got that: when a record existed on the page for the first one, if you want to add the X Lock on it, the supremum of pre-page will be add X Lock(maybe next key lock, supremum can be add gap lock only) also. In my case, the records' primary key stored like this: (..., 123440, supremum), (infimum, 123456, ...)， the id=123456 is the first record of that page, when add X Lock, first, find the pre-record id=123440, and then add the X lock after this record(id=123440) until match the record witch id=123456, so the supremum is locked also...， because of this lock(supremum)， session2 is blocked. if id=123456 is not the first record of page, session2 will not be blocked. so my doubt is: in my case, the session1 lock the supremum is necessary? if it's necessary, the lock on supremum maybe resulting the difference even if two mysql instances have the same records, just as in a replication. the record located on the page not all the same even if two instances have the same table sturcture & data(if slave define the table compressed, or innodb page_size not set as the same as master, etc..). if lock on supremum is neccessary, two instances execute the same SQLs, master is OK, but slave conflicted? on master， the two transactions may be committed in one group, but on slave maybe conflicted, slave's parallell replication is OK? also in MySQL 5.7.x, the xa prepare recorded in binlog, if on the master, execute two xa transactions: xa start 'aaa'; delete from table_name where id=xxxx; xa end 'aaa';xa prepare 'aaa'; xa start 'bbb';insert into table_name values(xxxx); end 'bbb'; xa prepare 'bbb'; xa commit 'aaa'; xa commit 'bbb' on the master, these xa not conflicted, I can committed these transaction, but on the slave, maybe conflicted sometimes, the replication is broken. how to repeat: create a table with primary key(id auto_increment is better) insert some records in this table use 3 sessions to find the first record on one page(perhaps, there are many pages, any one is OK).how to? session1: begin; select * from table_name where id=xxx for update // id=xxx must be exist session2: select * from table_name where id=xxx for update session3: when session2 is blocked, execute: show engine innodb status\G; in the transaction section, you can find some details like this: ------- TRX HAS BEEN WAITING 2 SEC FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 29 page no 2772 n bits 144 index PRIMARY of table `mydb`.`sbtest1` trx id 2388 lock_mode X insert intention waiting Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0 0: len 8; hex 73757072656d756d; asc supremum;; from the information "space id 29 page no 2772", we can find the page of this record. then test for next id until the page no become to 2773, remember this id, this record is the first one of page 2773 delete some records before this id witch get in step 3 use 2 sessions to do what i described I repeat it by sysbench(version 1.0). 1. use sysbench to create a table with 500,000 records: sysbench --table-size=500000 --tables=1 --threads=64 --create_secondary=false --db-driver=mysql --mysql-host=127.0.0.1 --mysql-port=3306 --mysql-user=root --mysql-db=mydb oltp_read_write.lua prepare 2. delete the records between(200000, 200057), delete from sbtest1 where id>200000 and id < 200057 3. two sessions: session1: begin;select * from sbtest1 where id=200057 for update; session2: insert into sbtest1 values(200050, 0,'a','a') session2 will be blocked by session1. Because this problem is related to the localtion of the record in the page, repeat it like my operations, do not use the compressed table and make sure the innodb_page_size = 16384. in my case, the Lock on supremum is neccessary? 2017-06-05 boyce@netease

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[Maria-developers] Progress report of the Project
by ANKIT KUMAR 05 Jun '17

05 Jun '17

Hi, I am Working on MDEV-11340 and by the end of the first week of Coding Period I have managed to learn How to use Bison. Currently thinking about How to implement subtask-1 of my project. Kind Regards,

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