May 2018 - developers - lists.mariadb.org

[Maria-developers] Windows line endings in MariaDB sources again (
by Otto Kekäläinen 24 Jul '19

24 Jul '19

Hello! While trying to release 10.0.26 for Debian and Ubuntu I noticed git chokes again on Windows line endings. As our .gitattributes states that by default git should clean up the line endings, why do we keep getting new Windows line endings in new code? mariadb-10.0$ cat .gitattributes # Set the default behavior, in case people don't have core.autocrlf set. * text=auto ... storage/connect/mysql-test/connect/std_data/*.txt -text mariadb-10.0.26$ find . | xargs file | grep CRLF ./storage/connect/mysql-test/connect/std_data/boyswin.txt: ASCII text, with CRLF line terminators ./storage/connect/mysql-test/connect/std_data/expenses.txt: ASCII text, with CRLF line terminators ./storage/connect/mysql-test/connect/std_data/emp.txt: ASCII text, with CRLF line terminators ./mysql-test/std_data/loaddata7.dat: ASCII text, with CRLF line terminators ./mysql-test/r/loadxml.result: ASCII text, with CRLF, LF line terminators ./mysql-test/r/perror-win.result: ASCII text, with CRLF, LF line terminators ./mysql-test/r/mysql_binary_mode.result: ASCII English text, with CRLF, LF line terminators ./mysql-test/r/func_regexp_pcre.result: UTF-8 Unicode C++ program text, with CRLF, CR, LF line terminators ./pcre/testdata/grepoutputN: ASCII text, with CRLF, CR, LF line terminators ./pcre/testdata/greppatN4: ASCII text, with CRLF line terminators This leads for me to: dpkg-source: info: building mariadb-10.0 using existing ./mariadb-10.0_10.0.26.orig.tar.gz dpkg-source: info: local changes detected, the modified files are: mariadb-10.0/storage/connect/mysql-test/connect/std_data/boyswin.txt mariadb-10.0/storage/connect/mysql-test/connect/std_data/emp.txt mariadb-10.0/storage/connect/mysql-test/connect/std_data/expenses.txt dpkg-source: error: aborting due to unexpected upstream changes, see /tmp/mariadb-10.0_10.0.26-1.diff.Yzwwhw Which means I have to do extra work with importing the upstream sources.. - Otto

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[Maria-developers] 10.2 and merges (e.g. TokuDB)
by Phil Sweeney 28 Aug '18

28 Aug '18

Hi there, It seems 10.2.6 is still shipping with TokuDB from PS 5.6.35-80 (Feb 8th 2017). I can't see a jira issue for a 10.2 merge since 10.2.4. Perhaps intentional to help stabilise 10.2 for release? 10.0.30 also shipped with the same Feb version (in March). 10.1.23 however was released in May and still has this version from Feb, which seems unfortunate, but I know it's because it has to flow through 10.0 first. I see 10.0.31 is due to get TokuDB from PS 5.6.36-82 And that should flow into 10.1.24 soon too. However, 10.2.7 isn't due until July, so by then TokuDB version will be 5 months old in 10.2 I'm waiting on a fairly important row count fix that should appear in the next Percona Server release. When it does, if the current merging strategy continues, do I have to first wait for 10.0.32 to get it in late July, then 10.1.26 in August, then 10.2 after that? Or with 10.0, 10.1 and 10.2 all being supported and needing merges, is there a new strategy on the cards to shorten this lag? Thanks! Phil

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[Maria-developers] Please review a patch for MDEV-15758 Split Item_bool_func::get_mm_leaf() into virtual methods in Field and Type_handler
by Alexander Barkov 20 Jul '18

20 Jul '18

Hello Vicentiu, Please review my patch for MDEV-15758. It also fixes this bug: MDEV-15759 Expect "Impossible WHERE" for indexed_int_column=out_of_range_int_constant Thanks!

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[Maria-developers] MDEV-13118 Wrong results with LOWER and UPPER and subquery
by Alexander Barkov 12 Jul '18

12 Jul '18

Hello Sergei, Please review a patch for MDEV-13118. Thanks!

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Re: [Maria-developers] 980a5c31880: MDEV-14572: Assertion `! is_set()' failed in Diagnostics_area::set_eof_status upon EXPLAIN UPDATE in PS
by Sergei Golubchik 19 Jun '18

19 Jun '18

Hi, Oleksandr! On Jan 28, Oleksandr Byelkin wrote: > Hi, Sergei! > > Flag in SELECT_LEX options dropped at the end of execution (in our case > prepare). All commands where EXPLAIN is possible restore the flag in main > SELECT_LEX (in mysql_explain_union()) except UPDATE (because it do > not use mysql_explain_union() > for explain). Without the flag it first try to send OK (as part of update) > then EOF as part of EXPLAIN. Ok. 1. Why does it not use mysql_explain_union() ? 2. Why EXPLAIN flag is need to be removed and restored anyway? 3. Please append the following to the commit comment: " Without it, mysql_update() didn't know that there will be EXPLAIN result set and was sending OK at the end of the update, which conflicted with the EOF sent later by EXPLAIN. " > On Sun, Jan 28, 2018 at 2:45 PM, Sergei Golubchik <serg(a)mariadb.org> wrote: > > > Hi, Oleksandr! > > > > On Dec 22, Oleksandr Byelkin wrote: > > > revision-id: 980a5c318803d6aa7355e019869597976dcf19bf (mariadb-10.0.33-37-g980a5c31880) > > > parent(s): 042f763268c0f209e7c12e0a6a72bb5d204dfe29 > > > author: Oleksandr Byelkin > > > committer: Oleksandr Byelkin > > > timestamp: 2017-12-22 14:00:10 +0100 > > > message: > > > > > > MDEV-14572: Assertion `! is_set()' failed in Diagnostics_area::set_eof_status upon EXPLAIN UPDATE in PS > > > > > > Restore EXPAIN flag in SELECT_LEX before execution multi-update by flag in LEX > > > (the same but in other way made before INSERT/DELETE/SELECT) > > > > Please explain what was the reason for the bug, why the status was set > > twice, and how your change fixes it. Regards, Sergei Chief Architect MariaDB and security(a)mariadb.org

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[Maria-developers] Proposal for Negative Grants Project
by Rutuja Surve 04 Jun '18

04 Jun '18

Hello, Please find the proposal for the Negative Grants project attached along with this e-mail. It would be great to hear your opinions and suggestions on the approach proposed here, before delving into its implementation. Some context about the project: *The current privilege system allows access in this manner:GRANT SELECT ON some_database.* TO a_user@%;Any revoke would revoke access from the entire database. We want to support a revoke that would disable select on a specific table, like:REVOKE SELECT ON some_database.secret_table FROM a_user@%;Reference:[1] https://jira.mariadb.org/browse/MDEV-14443 <https://jira.mariadb.org/browse/MDEV-14443>[2] https://mariadb.com/kb/en/library/google-summer-of-code-2018/ <https://mariadb.com/kb/en/library/google-summer-of-code-2018/>Thanks,Rutuja*

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[Maria-developers] Conservative parallel slave is "too optimistic" for certain engines
by Sergey Petrunia 01 Jun '18

01 Jun '18

Hello, This comes from MDEV-16242. == Symptoms == When one runs a parallel slave (mode=conservative) and replicates DML for MyRocks table without a Primary Key, replication may stop with a ER_KEY_NOT_FOUND error. This may happen even if the queries were run on the master sequentially. == A detail about conservative replication == Suppose the master runs these two statements, sequentially: INSERT INTO t1 VALUES (5),(6),(7); DELETE FROM t1; Parallel slave may schedule the INSERT to Thread1, and the DELETE to Thread2. In conservative parallel replication, the DELETE "will wait" to be executed after the INSERT. One may expect that "will wait" here means that DELETE execution does not start until the INSERT has committed. But it's more subtle than that: actually, DELETE execution will start as soon as the INSERT is ready to do the prepare/commit steps. I assume this was done to increase the parallelism: initial phases of DELETE can be ran in parallel with commit/prepare steps of the INSERT. This is safe to do: 1. The INSERT has acquired locks for all rows it is about to touch. DELETE will not be able to prevent INSERT from committing. 2. The DELETE starts its execution on a database that doesn't include the results of the INSERT (the INSERT has not committed yet!). But this is fine, because the DELETE locks the rows it is about to modify. If it attempts to access a row that the INSERT is about to insert, it will block on a lock until the INSERT finishes. == Applying this to MyRocks == The critical part is #2. It works if the DELETE command will acquire row locks for rows it about to DELETE. This is normally true: If the storage engine supports gap locks, attempting to read a locked gap will cause DELETE to wait for INSERT If the storage engine doesn't support gap locks, it will use Row-Based-Replication. RBR's Delete_rows_event includes Primary Key value of the row that should be deleted. Doing a point lookup on PK will cause the DELETE to block on the row lock. The remaining case is - storage engine that doesn't support gap locks - Row-based-replication of table without primary key In this case, finding the row to delete is done by scanning the table until we find the row where all columns match. The scan does not see the rows that the INSERT is about to INSERT, and DELETE stops with an error, "we could not find the row to delete". == Possible solutions == 1. Implement gap locking in MyRocks. This will take some time. 2. Change parallel slave to wait *for commit*. This should only be done if tables that are updated do not support Gap Locking. This is hard, it will require making risky changes on the SQL layer. 3. Disallow parallel slave execution for tables without Gap Locking and without primary key. (Looks most promising but I am not sure if it is sufficient). BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog

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[Maria-developers] With_sum_func_cache
by Alexander Barkov 31 May '18

31 May '18

Hello Sanja, I recently worked on MDEV-16309 and had hard time to find which Item classes in the hierarchy: - have always with_sum_func==true - have always with_sum_func==false - have variable with_sum_func To make it sure, before actually working on MDEV-16309, I had to create a separate working tree and did with Item::with_sum_func the same change that we previously did for Item::with_subselect in: MDEV-14517 Cleanup for Item::with_subselect and Item::has_subquery() (which you reviewed) - I find the code easier to read this way (instead of searching for all possible assignments, one can search who overrides the method) - Also, some Item can become smaller in size. It's pity to throw the patch away. So perhaps we could just apply it. Can you please have a look? Thanks. I the meanwhile I'll create a new MDEV for it (with a similar description to MDEV-14517)

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[Maria-developers] Open and close a TABLE_LIST at random place in code
by Eugene Kosov 31 May '18

31 May '18

Hello. I need to see a table structure while executing some query (DELETE in my case, but there will be more query types in future). I have a TABLE_LIST which came from a parser. Now I'm opening it with open_table_only_view_structure(), examine table structure and close it, trying to prevent any side effects. And there is a lot of them. Current code looks like this: if (open_tables_only_view_structure(thd, table_list, false)) { return true; } // examine table structure close_mysql_tables(thd); for (Sroutine_hash_entry *e = thd->lex->sroutines_list.first;e; e=e->next) e->mdl_request.ticket= NULL; for (TABLE_LIST *it= table_list; it; it= it->next_global) { it->table= NULL; it->reinit_before_use(thd); //it->next_global= NULL; it->derived_result= NULL; it->derived= NULL; it->view= NULL; it->view_tables= NULL; it->view_sctx= NULL; it->file_version= 0; it->mariadb_version= 0; it->updatable_view= 0; it->view_suid= 0; it->derived_type= 0; it->open_type= OT_BASE_ONLY; it->view_creation_ctx= 0; // it->set_table_ref_id(TABLE_REF_NULL, 0); } Is there a way to close a TABLE_LIST gracefully without touching a lot of it's fields? Or even maybe it's possible to open a table in a simpler manner? -- Eugene

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Re: [Maria-developers] [Commits] de722585c1b: MDEV-16225: wrong resultset from query with semijoin=on
by Sergey Petrunia 27 May '18

27 May '18

Hi Varun, On Thu, May 24, 2018 at 03:17:02AM +0530, Varun wrote: > revision-id: de722585c1b2ad2af99bd1749e8566ea77838764 (mariadb-5.5.56-219-gde722585c1b) > parent(s): 1ada4afb0a51f7283b6187a95019ec2cb80c8a0b > author: Varun Gupta > committer: Varun Gupta > timestamp: 2018-05-24 03:09:42 +0530 > message: > > MDEV-16225: wrong resultset from query with semijoin=on > > For non-semi-join subquery optimization we do a cost based decision between > Materialisation and IN -> EXIST transformation. The issue in this case is that for IN->EXIST transformation > we run JOIN::reoptimize with the IN->EXISt conditions and we come up with a new query plan. But when we compare > the cost with Materialization, we make the decision to chose Materialization so we need to restore the query plan > for Materilization. The restoring of query plan is not handled correctly. > > diff --git a/sql/sql_select.cc b/sql/sql_select.cc > index d6d269a700f..b8d43b9797e 100644 > --- a/sql/sql_select.cc > +++ b/sql/sql_select.cc > @@ -23805,6 +23805,22 @@ void JOIN::restore_query_plan(Join_plan_state *restore_from) > } > > } > + else > + { > + /* > + After running JOIN::reoptimize for IN->EXISTS > + transformation we might add elements to the keyuse array, > + The original query plan was that the keyuse array had no elements, so we > + should restore that state here. > + */ > + while(keyuse.elements) > + delete_dynamic_element(&keyuse, 0); I'm wondering, why do we need the above loop and not just delete everything with delete_dynamic(). But if I don't miss anything, this is not significant. Ok to push either the above variant or one with delete_dynamic(). > + for (uint i= 0; i < table_count; i++) > + { > + join_tab[i].keyuse= NULL; > + join_tab[i].checked_keys.clear_all(); > + } > + } > memcpy((uchar*) best_positions, (uchar*) restore_from->best_positions, > sizeof(POSITION) * (table_count + 1)); > /* Restore SJM nests */ > _______________________________________________ > commits mailing list > commits(a)mariadb.org > https://lists.askmonty.org/cgi-bin/mailman/listinfo/commits -- BR Sergei -- Sergei Petrunia, Software Developer MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog

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