March 2015 - developers - lists.mariadb.org

Re: [Maria-developers] [Commits] Rev 4382: MDEV-6892: WHERE does not apply in file:///home/bell/maria/bzr/work-maria-5.5-MDEV-6892/
by Sergey Petrunia 11 Mar '15

11 Mar '15

Hi Sanja, Please find my feedback below. We should discuss it. On Fri, Dec 19, 2014 at 01:24:12PM +0000, sanja(a)askmonty.org wrote: > At file:///home/bell/maria/bzr/work-maria-5.5-MDEV-6892/ > > ------------------------------------------------------------ > revno: 4382 > revision-id: sanja(a)askmonty.org-20141219132350-6bo1g7q6gbivqdky > parent: svoj(a)mariadb.org-20141201105829-ctaoe194abtorhz2 > committer: sanja(a)askmonty.org > branch nick: work-maria-5.5-MDEV-6892 > timestamp: Fri 2014-12-19 14:23:50 +0100 > message: > MDEV-6892: WHERE does not apply > > Taking into account implicit dependence of constant view field from nullable table of left join added. > > Fixed finding real table to check if ut turned to NULL (materialized view & derived taken into account) ... > === modified file 'sql/item.cc' > --- a/sql/item.cc 2014-10-06 17:53:55 +0000 > +++ b/sql/item.cc 2014-12-19 13:23:50 +0000 > @@ -9790,12 +9790,36 @@ void Item_ref::update_used_tables() > (*ref)->update_used_tables(); > } > > +void Item_direct_view_ref::update_used_tables() > +{ > + if (view->is_inner_table_of_outer_join()) > + { > + null_ref_table= NULL; > + check_null_ref(); update_used_tables() is called during optimization. Why does it call check_null_ref() which may check null_ref_table->null_row? Is check_null_ref() function an execution-time function (and so it computes "current" value of an item) or is it an optimization-time function (and so it computes static attributes and can be called at any point in the query) It looks like it's a bit of both, which is really confusing. Could you please clarify? check_null_ref() was introduced by you in another views+outer joins bugfix. Can we get it documented? > + } > + Item_direct_ref::update_used_tables(); > +} Overall, I don't understand why some checks are in used_tables() and some are in update_used_tables(). Could you clarify? > + > table_map Item_direct_view_ref::used_tables() const > { > + TABLE *null_ref= null_ref_table; > + > + if (view->is_inner_table_of_outer_join()) > + { > + if (null_ref == NULL) > + null_ref= view->get_real_join_table(); > + else if (null_ref == NO_NULL_TABLE) > + null_ref= NULL; > + } > + else > + null_ref= NULL; > + > return get_depended_from() ? > OUTER_REF_TABLE_BIT : > ((view->is_merged_derived() || view->merged || !view->table) ? > - (*ref)->used_tables() : > + ((*ref)->used_tables() ? > + (*ref)->used_tables() : > + (null_ref ? null_ref->map : (table_map)0 )) : > view->table->map); Two-level nesting of conditional expressions is too complicated. Please change into 'if' statement and a comment about what's going on. How can Item_direct_view_ref() deped on an outer table?? > } > > > === modified file 'sql/item.h' > --- a/sql/item.h 2014-11-18 14:42:40 +0000 > +++ b/sql/item.h 2014-12-19 13:23:50 +0000 > @@ -3319,7 +3319,8 @@ class Item_direct_view_ref :public Item_ > { > if (null_ref_table == NULL) > { > - if (!(null_ref_table= view->get_real_join_table())) > + if (!view->is_inner_table_of_outer_join() || > + !(null_ref_table= view->get_real_join_table())) > null_ref_table= NO_NULL_TABLE; > } > if (null_ref_table != NO_NULL_TABLE && null_ref_table->null_row) > @@ -3329,6 +3330,7 @@ class Item_direct_view_ref :public Item_ > } > return FALSE; > } > + > public: > Item_direct_view_ref(Name_resolution_context *context_arg, Item **item, > const char *table_name_arg, > @@ -3353,8 +3355,10 @@ public: > bool subst_argument_checker(uchar **arg); > Item *equal_fields_propagator(uchar *arg); > Item *replace_equal_field(uchar *arg); > - table_map used_tables() const; > + table_map used_tables() const; > + void update_used_tables(); > table_map not_null_tables() const; > + bool const_item() const { return used_tables() == 0; } > bool walk(Item_processor processor, bool walk_subquery, uchar *arg) > { > return (*ref)->walk(processor, walk_subquery, arg) || > > === modified file 'sql/table.cc' > --- a/sql/table.cc 2014-10-29 10:22:48 +0000 > +++ b/sql/table.cc 2014-12-19 13:23:50 +0000 The function get_real_join_table() lacks comments, which makes it difficult to review. Do I understand correctly that its action can be described by this comment: /* @brief Given a merged view (or a merged derived table), find its first* base** table. @detail (*) first means as defined in the syntax (**) base means we need a physical table, one that has a bit in table->map and is present in select_lex->leaf_tables. Example: t1 join ( (select * from t2, t3 ) as derivedA join (select * from t5, t6) as derivedC ) as derivedB here, derivedB->get_real_join_table()="t2" */ > @@ -5012,7 +5012,8 @@ TABLE *TABLE_LIST::get_real_join_table() > TABLE_LIST *tbl= this; > while (tbl->table == NULL || tbl->table->reginfo.join_tab == NULL) I'm quite surprised that joins are run over tables that don't have reginfo.join_tab set appropriately... > { > - if (tbl->view == NULL && tbl->derived == NULL) > + if ((tbl->view == NULL && tbl->derived == NULL) || > + tbl->is_materialized_derived()) I'm wondering why part of conditions are in while(...) and the other part is here. > break; > /* we do not support merging of union yet */ > DBUG_ASSERT(tbl->view == NULL || > The code below this line looks bizarre (and it is still from your recent fixes to VIEWs): { List_iterator_fast<TABLE_LIST> ti; { List_iterator_fast<TABLE_LIST> ti(tbl->view != NULL ? why define 'ti' and then immediately redefine it? BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog

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Re: [Maria-developers] f954bb7: MDEV-7671: Cache VIEW definitions in the TDC
by Sergei Golubchik 11 Mar '15

11 Mar '15

Hi, Sanja! On Mar 10, sanja(a)mariadb.com wrote: > revision-id: f954bb7fdc527cf816253fe0e7adb4239c368624 > parent(s): f7d196bb2e605766668895027c48728f03803734 > committer: Oleksandr Byelkin > branch nick: server > timestamp: 2015-03-10 12:52:45 +0100 > message: > > MDEV-7671: Cache VIEW definitions in the TDC > > (changes of backported patch are very small: strlen removed, error > processing fixed, view open statistics added) Ok to push Regards, Sergei

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[Maria-developers] GSOC 2015: Support for popular formats on Dynamic columns.
by arlene seuleu 11 Mar '15

11 Mar '15

Hi I am Arlene Flavie a software Engineering student and I wish to make my contribution to opensource through Mariadb. I have build mariadb from a git clone and ran the tests. I am interested in working on adding routines to import and export popular data formats to and from dynamic columns. I am currently studying the dynamic column data structures in mysql/ma_dyncol.** and I think what Oleksandr Byeklin proposed makes sense to me. Thats using methods like xxx_init() and xxx_named() to play with the old dynamic column blob format. I will be applying to work on this task for Gsoc 2015 and im hoping to learn much in open source development. Cheers.

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[Maria-developers] Interest in GSoc
by Acha Bill 11 Mar '15

11 Mar '15

Hello, I am Acha Bill, Computer Engineering, University of Buea, Cameroon. Second year undergraduate. I am very much interested in the project; Import and export popular data formats from and to dynamic columns. for Gsoc 15. I have experience with C. Any pointers as to what next will be appreciated. Thanks.

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Re: [Maria-developers] [Maria-discuss] Enabling feedback pluging for MariaDB 10.1.4
by Justin Swanhart 11 Mar '15

11 Mar '15

It tells you how much a sample used and you don't know what fraction of the total that represents, or if their usage is representative of the larger base. I maintain they are not meaningful but you can feel free to disagree. Sent from my iPhone > On Mar 10, 2015, at 7:42 PM, Michael Widenius <michael.widenius(a)gmail.com> wrote: > > Hi! > > <cut> > >> I agree with Kristian. Given the way it works, the statistics are really meaningless and I feel you shouldn't drive important choices based on bad statistics. > > From a statistics point of view, the automatic feedback will tell us a > lot about how people use MariaDB and is far from meaningless! > (We only need a small statistical sample to know how the majority is > using the server). > > The most important things for our developers, that the phone home > feature will tell us, are probably: > - Features that are used (and how much they are used) > - Features that not used. > - Combinations of features used. > - The stability of the servers. > - How often upgrades are done > > This will allow us to better concentrate the few development resources > on features that are important to our users. > > In the past, our main problem for allocating resources has always been > "does anyone really use or care about this". Now we finally will get > some information to make these kind of decisions easier. > > Regards, > Monty

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[Maria-developers] GSOC 2015 :UDFs returning arrays
by Blessing Atie 10 Mar '15

10 Mar '15

Hi My name is Blessing Atie and i would love to participate in the Google summer of code 2015 under Mariadb. I am interested in the project UDF returning arrays. I have build mariadb from source and and i also ran the test suites. I am currently studing the sql/sql.** files to understand UDF's and i also downloaded some ebook on mysql internals and mysql plugin development which im reading while hoping to find a breakthrough on this project in them. I would love to know if there are any bugs related to this task on JIRA I could work on as a means of preparing for the project. Please give me the link. Regards Blessing.

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Re: [Maria-developers] [Commits] 83659a6: MDEV-7006 MDEV-7007: SET STATEMENT and slow log
by Sergei Golubchik 10 Mar '15

10 Mar '15

Hi, Sanja! On Feb 17, sanja(a)mariadb.com wrote: > revision-id: 83659a68642da2eb6e9327f17a0ef730f512aa96 > parent(s): 3e2849d2a01b06a61407b00989c3f981e62dd183 > committer: Oleksandr Byelkin > branch nick: server > timestamp: 2015-02-17 12:54:51 +0100 > message: > > MDEV-7006 MDEV-7007: SET STATEMENT and slow log > fixed embedded server tests > MDEV-7009: SET STATEMENT min_examined_row_limit has no effect > MDEV-6948:SET STATEMENT gtid_domain_id = ... FOR has no effect (same for gtid_seq_no and server_id) > > old values of SET STATENENT variables now saved in its own Query_arena and restored later Looks good to me. I didn't check, though, whether you've put every restore correctly. See minor comments below: > diff --git a/mysql-test/t/set_statement_notembedded_binlog.test b/mysql-test/t/set_statement_notembedded_binlog.test > new file mode 100644 > index 0000000..c9c2334 > --- /dev/null > +++ b/mysql-test/t/set_statement_notembedded_binlog.test > @@ -0,0 +1,22 @@ > +--source include/have_log_bin.inc > +--source include/not_embedded.inc > + > +--disable_warnings > +drop table if exists t1; > +drop view if exists t1; > +--enable_warnings This was useful in our early MySQL days, but it's not anymore. I've stopped adding these drop...if exists at the beginning of test files a couple of years ago. mtr has a after-test check to ensure that no test leaves its tables behind. So one can rely on every test starting clean. > + > +--echo # > +--echo # MDEV-6948: SET STATEMENT gtid_domain_id = ... FOR has no effect > +--echo # (same for gtid_seq_no and server_id) > +--echo # > +reset master; > +create table t1 (i int); > +set gtid_domain_id = 10; > +insert into t1 values (1),(2); > +set statement gtid_domain_id = 20 for insert into t1 values (3),(4); > + > +--replace_column 1 x 2 x 3 x 4 x 5 x > +show binlog events limit 5,5; > + > +drop table t1; > diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc > index 0c1c3b3..ee956ed 100644 > --- a/sql/sql_lex.cc > +++ b/sql/sql_lex.cc > @@ -4223,6 +4224,56 @@ int LEX::print_explain(select_result_sink *output, uint8 explain_flags, > return res; > } > > +void LEX::set_arena_for_set_stmt(Query_arena *backup) > +{ > + DBUG_ENTER("LEX::set_arena_for_set_stmt"); > + DBUG_ASSERT(arena_for_set_stmt== 0); > + if (!mem_root_for_set_stmt) > + { > + mem_root_for_set_stmt= new MEM_ROOT(); > + if (!(mem_root_for_set_stmt)) > + DBUG_VOID_RETURN; What happens in OOM case? You return early, but does the caller know that? Or it'll continue, thinking that everything's ok? > + init_sql_alloc(mem_root_for_set_stmt, ALLOC_ROOT_SET, ALLOC_ROOT_SET, > + MYF(MY_THREAD_SPECIFIC)); > + } > + if (!(arena_for_set_stmt= new Query_arena(mem_root_for_set_stmt, Why are you allocating memory for Query_arena, instead of creating it on mem_root_for_set_stmt? > + Query_arena::STMT_INITIALIZED))) > + DBUG_VOID_RETURN; > + DBUG_PRINT("info", ("mem_root: 0x%lx arena: 0x%lx", > + (ulong) mem_root_for_set_stmt, > + (ulong) arena_for_set_stmt)); > + thd->set_n_backup_active_arena(arena_for_set_stmt, backup); > + DBUG_VOID_RETURN; > +} > + > + > +void LEX::reset_arena_for_set_stmt(Query_arena *backup) > +{ > + DBUG_ENTER("LEX::reset_arena_for_set_stmt"); > + DBUG_ASSERT(arena_for_set_stmt); > + thd->restore_active_arena(arena_for_set_stmt, backup); > + DBUG_PRINT("info", ("mem_root: 0x%lx arena: 0x%lx", > + (ulong) arena_for_set_stmt->mem_root, > + (ulong) arena_for_set_stmt)); > + DBUG_VOID_RETURN; > +} > + > + > +void LEX::free_arena_for_set_stmt() > +{ > + DBUG_ENTER("LEX::free_arena_for_set_stmt"); > + if (!arena_for_set_stmt) > + return; > + DBUG_PRINT("info", ("mem_root: 0x%lx arena: 0x%lx", > + (ulong) arena_for_set_stmt->mem_root, > + (ulong) arena_for_set_stmt)); > + arena_for_set_stmt->free_items(); > + delete(arena_for_set_stmt); > + free_root(mem_root_for_set_stmt, MYF(MY_KEEP_PREALLOC)); > + arena_for_set_stmt= 0; > + DBUG_VOID_RETURN; > +} > + > void LEX::restore_set_statement_var() > { > DBUG_ENTER("LEX::restore_set_statement_var"); > diff --git a/sql/sql_lex.h b/sql/sql_lex.h > index 46d667c..ed3c4a0 100644 > --- a/sql/sql_lex.h > +++ b/sql/sql_lex.h > @@ -2677,10 +2688,22 @@ struct LEX: public Query_tables_list > limit_rows_examined_cnt= ULONGLONG_MAX; > } > > + > + inline void free_set_stmt_mem_root() > + { Please, add DBUG_ASSERT(!is_arena_for_set_stmt()); > + if (mem_root_for_set_stmt) > + { > + free_root(mem_root_for_set_stmt, MYF(0)); > + delete mem_root_for_set_stmt; > + mem_root_for_set_stmt= 0; > + } > + } > + > LEX(); > > virtual ~LEX() > { > + free_set_stmt_mem_root(); > destroy_query_tables_list(); > plugin_unlock_list(NULL, (plugin_ref *)plugins.buffer, plugins.elements); > delete_dynamic(&plugins); Regards, Sergei

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[Maria-developers] GSOC 2015: Indexes on virtual columns
by Sichom Lionel 10 Mar '15

10 Mar '15

Hello, My name is Lionel Sichom, 2nd year undergraduate student at the University of Buea. I am a newbie in Open source community and I am interested in participating at the Google Summer of Code 2015 with MariaDB. I am mostly interested with the project Indexes on virtual columns. As for now I have 5.5.41-MariaDB version and I have already downloded the code, and I am already compiling the code. Can someone please guide me through the steps next to follow. Thanks Lionel Sichom

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[Maria-developers] Question regarding MDEV-7682
by Vicențiu Ciorbaru 10 Mar '15

10 Mar '15

Hi Holyfoot! I've made some changes regarding key_length computation to fix MDEV-6838. Changing this seems to have lead to us discovering another issue outlined in MDEV-7682 (that I've just created). It seems that the spatial key returns a key_length of 0. I've spoken to Sergei Petrunia and we are not sure about this particular case. pack_length returns a bigger number (12). According to the other comments in the code, pack_length also returns the length field associated with the column, but we are only interested in the length of the column field, without any metadata information. The function TABLE:create_key_part_by_field adds the metadata length itself afterwards. Do you have any input on this issue, namely why the key_length is returned as 0 for the LINESTRING column? Regards, Vicentiu

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[Maria-developers] [GSoC'15] Running MaxScale and MariaDB servers on single machine
by sriram patil 09 Mar '15

09 Mar '15

Hi All, I tried running 2 MariaDB servers and MaxScale on my laptop. I gave different configurations to both MariaDB servers with separate data and log directories. Referred this <http://www.ducea.com/2009/01/19/running-multiple-instances-of-mysql-on-the-…> for it. Also have set up MaxScale from "MaxScale for rest of us" series on MariaDB blog. 1. https://mariadb.com/blog/maxscale-rest-us-part-1 2. https://mariadb.com/blog/maxscale-rest-us-part-2 3. https://mariadb.com/blog/maxscale-rest-us-part-3 4. https://mariadb.com/blog/maxscale-rest-us-part-4 So, i tried to set up the readwritesplit router with 1 master and 1 slave. Here, the replication mechanism worked fine but the queries are always executed on the master server. Example output for a read query: mysql -h localhost -u maxuser -p test -e "select c1, @@server_id from t1" Enter password: +------+-------------+ | c1 | @@server_id | +------+-------------+ | 1 | 1 | +------+-------------+ server_id for master is 1 whereas for slave it is 11, which is never displayed in the output. Can someone help me with this? Should I try the same config with one more slave? Are there any better resources for setting up MaxScale? Thanks, Sriram

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