Meet MariaDB Vicențiu Ciorbaru Software MariaDB Foundation * * 2017 MariaDB Foundation

Transcription

1 Meet MariaDB 10.3 Vicențiu Ciorbaru Software MariaDB Foundation vicentiu@mariadb.org * *

2 What is MariaDB? MariaDB 5.1 (Feb 2010) - Making builds free MariaDB 5.2 (Nov 2010) - Community features MariaDB 5.3 (Apr 2012) - New optimizer MariaDB 5.5 (Apr 2013) - Merge with MySQL MariaDB 10.0 (Mar 2014) - Parallel replication MariaDB 10.1 (Oct 2015) - Galera, Encryption MariaDB 10.2 (Apr 2017) - Advanced features MariaDB 10.3 (??? 2017) - Compatibility

3 Brief History of MariaDB Created as a response to Oracle s acquisition of MySQL Named after Monty s youngest daughter Maria First release in Oct 2009, MariaDB 5.1 The development is guided by the MariaDB Foundation Strong focus on community development, not just in-house Now the default MySQL variant in Debian 9

4 Goal of 10.3 Make it as easy as possible to migrate to MariaDB Migrating from MySQL usually just works How to migrate when you have proprietary applications, written for Oracle DB? Use 80/20 Principle 20% work for 80% of use cases Implement compatibility rules

5 Sequences CREATE [OR REPLACE] [TEMPORARY] SEQUENCE [IF NOT EXISTS] sequence_name [ INCREMENT [ BY = ] increment ] [ MINVALUE [=] minvalue NO MINVALUE NOMINVALUE ] [ MAXVALUE [=] maxvalue NO MAXVALUE NOMAXVALUE ] [ START [ WITH = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ] [table_options] NEXT VALUE FOR sequence_name NEXTVAL(sequence_name) sequence_name.nextval PREVIOUS VALUE FOR sequence_name LASTVAL(sequence_name) sequence_name.currval are supported

6 AS OF (Temporal Tables Support) Allows querying of past data (before updates / deletes) Works transparently with past applications Can prune historical data as necessary

7 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning T0 T1 T2 T3

8 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill T0 T1 T2 T3 insert into emp values ( Bill, 1000, 10)

9 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill T0 T1 T2 T3 insert into emp values ( Bill, 1000, 10) update emp set salary=2000 where name = Bill

10 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill Bill T0 T1 T2 T3 insert into emp values ( Bill, 1000, 10) update emp set salary=2000 where name = Bill update emp set dept=20 where name = Bill

11 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill Bill T0 T1 T2 T3 select * from emp where name = Bill

12 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill Bill T0 T1 T2 T3 select * from emp where name = Bill select * from emp for system_time as of where name = Bill

13 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill Bill T0 T1 T2 T3 select * from emp where name = Bill select * from emp for system_time as of where name = Bill

14 AS OF Example create table emp ( name varchar(30), salary int, dept int ) with system versioning Bill Bill Bill T0 T1 T2 T3 select name, salary, dept from emp for system_time between and

15 AS OF (Temporal Tables Support) Managing Temporal Support alter table emp with system versioning truncate table emp for system_time before timestamp ' :03:03'; truncate table emp for system_time timestamp between ' :00:01' and ' :59:59';

16 INTERSECT & EXCEPT (select a,b from t1) INTERSECT (select c,d from t2) Returns only rows that are in both SELECTs T1 T2 (select a,b from t1) EXCEPT (select c,d from t2) Returns rows that are in first SELECT but not in second SELECT T1 T2

17 ROW data type for stored routines ROW data type <row type> <row type body> ::= ROW <row type body> ::= <left paren> <field definition> [ { <comma> <field definition> }... ] <right paren> <field definition> ::= <field name> <data type> <data type> ::= <predefined type> CREATE PROCEDURE p1() BEGIN DECLARE a ROW (c1 INT, c2 VARCHAR(10)); SET a.c1= 10; SET a.c2= 'test'; INSERT INTO t1 VALUES (a.c1, a.c2); END; CALL p1();

18 TYPE OF and ROW TYPE OF DECLARE tmp TYPE OF t1.a; Get the data type from the column a in the table t1 DECLARE rec1 ROW TYPE OF t1; Get the row data type from the table t1 DECLARE rec2 ROW TYPE OF cur1; Get the row data type from the cursor cur1

19 Cursors with parameters DECLARE cursor_name CURSOR FOR select_statement; OPEN cursor_name; Is extended with parameters: DECLARE cursor_name [cursor_formal_parameter [,...]] CURSOR FOR select_statement; cursor_formal_parameter: name type [collate clause] OPEN cursor_name [expression [,...]]; DECLARE cur CURSOR(pmin INT, pmax INT) FOR SELECT a FROM t1 WHERE a BETWEEN pmin AND pmax; OPEN cur (select 1), (select 10);

20 Catch-all for list partitions Add catch-all to all table partitioning for list partitions: PARTITION BY LIST (partitioning_expression) ( PARTITION partition_name VALUES IN (value_list), [ PARTITION partition_name VALUES IN (value_list),... ] [ PARTITION partition_name DEFAULT ] ) PARTITION BY LIST (id mod 2) ( PARTITION even VALUES IN (0), PARTITION odd VALUES IN (1), PARTITION nulls DEFAULT )

21 WAIT and NO_WAIT Provides a way to set lock wait timeout for some statement. Previously it was only global or session variable. select... for update [wait [n] no_wait] select... lock in share mode [wait [n] no_wait] lock table... [wait [n] no_wait] alter table t [wait [n] no_wait] add f int drop table [wait [n] no_wait]

22 Custom Aggregate Functions Define functions that can be used for aggregation like SUM or AVG CREATE AGGREGATE FUNCTION function_name (param, [param...]) RETURNS return_type BEGIN [variable declarations] DECLARE CONTINUE HANDLER FOR NOT FOUND RETURN ret_val; LOOP FETCH GROUP NEXT ROW; // next row from group [ sql expressions... ] END LOOP; END Can implement median, mode, etc. select sum(price * volume), cust_median(price * volume) from sales group by product;

23 Hidden Columns A. Not hidden normal columns created by the user B. A little bit hidden Columns that the user has marked hidden. Not shown in SELECT * Don t require values in INSERT table VALUE (...). C. More hidden Can be queried explicitly, otherwise hidden from everything, including CREATE and ALTER. Similar to ROWID pseudo-column. D. Very hidden as more hidden, but cannot be queried either. Show up in EXPLAIN EXTENDED. May be indexed.

24 Extended support for window functions More window functions supported PERCENTILE_CONT, PERCENTILE_DISC, MEDIAN Performance improvements in some cases (MIN/MAX)

25 New Oracle compatible parser Providing compatibility for basic PL/SQL constructs with new parser SET SQL_MODE=ORACLE; CREATE PROCEDURE sp1 (p1 IN VARCHAR2, p2 OUT VARCHAR2) IS v1 VARCHAR2(100); BEGIN v1 := p1; p2 := v1; END;

26 Compatibility parser LABEL and order of IN, OUT, INOUT MariaDB syntax CREATE PROCEDURE p1 (OUT param INT) Oracle Syntax CREATE PROCEDURE p1 (param OUT INT) label: SELECT GOTO label; <<label>> SELECT GOTO label;

27 Compatibility parser AS, IS keywords Oracle requires AS or IS keyword before body of function: CREATE FUNCTION f1 RETURN NUMBER AS BEGIN RETURN 10; END;

28 Compatibility parser EXIT statement MariaDB syntax: IF bool_expr THEN LEAVE label Oracle syntax to leave a loop block: EXIT [ label ] [ WHEN bool_expr ]

29 Compatibility parser assignment MariaDB syntax: SET var = 10; Oracle: var := 10; Assignment operator works for MariaDB system variables: max_sort_length := 1025;

30 Compatibility parser EXCEPTION MariaDB uses DECLARE HANDLER to catch exceptions: BEGIN DECLARE EXIT HANDLER FOR SQLEXCEPTION BEGIN.. END; END; In Oracle, exception handlers are declared at the end of a block: BEGIN... EXCEPTION WHEN OTHERS THEN BEGIN.. END; END;

31 Compatibility parser function parameters If no parameters, then parentheses must be omitted: CREATE PROCEDURE p1 AS BEGIN NULL; END; IN OUT instead of INOUT CREATE PROCEDURE p1 (a IN OUT INT) AS BEGIN END;

32 Compatibility parser RETURN Oracle uses RETURN, rather than RETURNS for function return type: CREATE FUNCTION f1(a INT) RETURN INT MariaDB supports RETURNS only in stored functions. Oracle supports RETURN in stored procedures as well CREATE PROCEDURE p1 (a IN OUT INT) AS BEGIN IF a < 10 THEN RETURN; END IF; a:=a+1; EXCEPTION WHEN OTHERS THEN RETURN; END;

33 Compatibility parser WHILE & CONTINUE MariaDB syntax: [begin_label:] WHILE search_condition DO statement_list END WHILE [end_label] Oracle syntax: [<<label>>] WHILE boolean_expression LOOP statement... END LOOP [ label ] ; CONTINUE statement: CONTINUE [ label ] [ WHEN boolean_expression ] ; This is a replacement for the ITERATE statement in MariaDB. CONTINUE is valid only inside a LOOP.

34 Compatibility parser datatypes VARCHAR2 - a synonym to VARCHAR NUMBER - a synonym to DECIMAL DATE (with time portion) - a synonym to DATETIME RAW - a synonym to VARBINARY CLOB - a synonym to LONGTEXT BLOB - a synonym to LONGBLOB

35 Compatibility parser %TYPE in variable declarations table%rowtype in variable declarations cursor%rowtype in variable declarations FOR loop statement Implicit and Explicit cursor FOR loop Implicit cursor FOR LOOP for cursors with parameters Explicit cursor attributes %ISOPEN, %ROWCOUNT, %FOUND, %NOTFOUND Variable declarations can go after cursor declarations Predefined exceptions: TOO_MANY_ROWS, NO_DATA_FOUND, DUP_VAL_ON_INDEX RAISE statement for predefined exceptions User defined exceptions

36 Compatibility parser SP control functions SQLCODE, SQLERRM Triggers: Understand :NEW.c1 and :OLD.c1 instead of NEW.c1 and OLD.c1 Dynamic SQL placeholders Allow VARCHAR and VARCHAR2 without length as a data type of routine parameters and in RETURN clause CAST(..AS VARCHAR(N)) Anonymous blocks GOTO statement Allow SELECT UNIQUE as a synonym for SELECT DISTINCT Do not require BEGIN..END in multi-statement exception handlers in THEN clause

37 Compatibility parser Understand optional routine name after the END keyword Inside routines the CALL keywoard is optional Make the concatenation functions ignore NULL arguments TRUNCATE TABLE t1 [ {DROP REUSE} STORAGE

38 10.3: PACKAGES A package is a schema object that groups logically related PL/SQL data types, items (e.g. variables, cursors, exceptions) and subprograms. CREATE PACKAGE CREATE PACKAGE BODY ALTER PACKAGE DROP PACKAGE BODY DROP PACKAGE

39 Features planned for 10.3 Compressed columns (Patch from Tencent) SPIDER storage engine update

40 Nice to have features for 10.3 Galera 4 (unlikely, no GA date announced) Timestamp with timezone Data type: Array Add sub-partitioning by LIST and RANGE Table functions (aka SQL functions returning tables)

41 Thank You! Contact me at: Blog: vicentiu.ciorbaru.io mariadb.org/blog 2016 MariaDB Foundation