MySQL overview

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  • 1. MySQL Overview 
 a quick look at the general aspects of the most popular open source databaseMarco TusaMySQL Team Leader16 September 2011
  • 2. Why Companies Trust Pythian • Recognized Leader: •  Global industry-leader in remote database administration services and consulting for Oracle, Oracle Applications, MySQL and SQL Server •  Work with over 150 multinational companies such as Forbes.com, Fox Interactive media, and MDS Inc. to help manage their complex IT deployments • Expertise: •  One of the world’s largest concentrations of dedicated, full-time DBA expertise. • Global Reach & Scalability: •  24/7/365 global remote support for DBA and consulting, systems administration, special projects or emergency response22 © 2010/2011 Pythian
  • 3. Why Companies Trust Pythian • Recognized Leader: •  Global industry-leader in remote database administration services and consulting for Oracle, Oracle Applications, MySQL and SQL Server •  Work with over 150 multinational companies such as Toyota, Fox Interactive media, and MDS Inc. to help manage their complex IT deployments • Expertise: •  One of the world’s largest concentrations of dedicated, full-time DBA expertise. • Global Reach & Scalability: •  24/7/365 global remote support for DBA and consulting, systems administration, special projects or emergency response32 © 2010/2011 Pythian
  • 4. Who I am •  Currently: Team Lead at The Pythian Group for MySQL database support •  Manager Professional Service South EMEA at MySQL/SUN/Oracle •  In MySQL before the SUN gets on us •  Leadingthe team responsible for Oracle & MySQL DBs service in support to technical systems, at Food and Agriculture Organization of United Nations (FAO of UN) •  Leading developer & system administrator teams in FAO managing the Intranet/Internet infrastructure. •  Working(a lot) in developing countries like (Ethiopia, Senegal, Ghana, Egypt …) •  My Profile http://it.linkedin.com/in/marcotusa34 © 2010/2011 Pythian
  • 5. What is MySQL? • MySQL is a database management system • MySQL is a relational database management system • MySQL software is Open Source. • MySQL Server works in client/server or embedded systems. • The official way to pronounce “MySQL” is “My Ess Que Ell” (not “my sequel”)20 5 © 2010/2011 Pythian
  • 6. Who is using MySQL List of customer from MySQL official presentation20 6 © 2010/2011 Pythian
  • 7. Main insight on MySQL 1/2 • Written in C and C++. • Works on many different platforms: •  FreeBSD 5.x. •  HP-UX 11.x. •  Linux. •  Mac OS X. •  Solaris 2.8 on SPARC and x86 •  Windows XP, Windows Vista, Windows Server 2003, and Windows Server 2008.20 7 © 2010/2011 Pythian
  • 8. Main insight on MySQL 2/2 • Uses multi-layered server design with independent modules. • Designed to be fully multi-threaded using kernel threads, to easily use multiple CPUs if they are available. • Provides transactional and non-transactional storage engines. • Designed to make it relatively easy to add other storage engines. This is useful if you want to provide an SQL interface for an in-house database. • Uses a very fast thread-based memory allocation system. • Full Localization support20 8 © 2010/2011 Pythian
  • 9. What Standards MySQL Follows? • Supports the full ANSI/ISO SQL standard, but with some flexibility (SQL-92=1992 Release; SQL:1999=1999 Release; SQL:2003=2003 Release; SQL:2008= 2008 Release). http://www.iso.org/iso/home.htm • ODBC levels 0 to 3.51. • MySQL can adapt its behavior using SQL Modes like: •  ANSI (SET GLOBAL sql_mode=ANSI;) •  Oracle •  Custom … • MySQL DATA is structured on the file system by directory and subdirectory (symbolic links widely used)20 9 © 2010/2011 Pythian
  • 10. Installing MySQL in 4 easy steps Installing MySQL is a simple operation: 1.  ownload software from site like (http://dev.mysql.com/get/ D Downloads/MySQL-5.5/mysql-5.5.15-linux2.6-x86_64.tar.gz/from/http:// mirror.csclub.uwaterloo.ca/mysql/) 2.  xpand it in /usr/local/mysql (and set all grants for mysql user) E 3.  opy one of the pre-configured my.cnf (from support-files C directory) to /etc/my.cnf; copy from same source mysql.server file to /etc/init.d/mysql 4.  tart mysql /etc/init.d/mysql start S You can have MySQL running in 30 minutes.20 1 © 2010/2011 Pythian 0
  • 11. MySQL Architecture 1/2 MySQL is composed of two main layers20 1 © 2010/2011 Pythian 1
  • 12. MySQL Architecture 2/2 • MySQL Layer (Parser; Optimizer; Query cache; threads handling ) •  Storage engines: •  MyISAM ( no ACID) •  Innodb (ACID) •  Cluster (ACID) •  Archive (only archive and append) •  Memory (Main engine for in memory operations) •  Blackhole (it is exactly what the name indicate) •  .. many others20 1 © 2010/2011 Pythian 2
  • 13. MySQL Storage engine more details 1/2 They have different advantages / trade-offs - know when to use them. 1.  yISAM M •  No transaction handling; no isolation level; no data buffered (only index); full Table lock; no foreign key; •  Fully file base; minimal overhead in write; very fast in reading; Btree index; Full text search; Geospatial support; 256TB Storage limit; 2. nnoDB I •  No full text (5.6 will); no Geospatial support; no cluster support; 64TB Storage limit; •  Full ACID; possible to modify the Isolation level; data is buffered; Write lock by ROW; Foreign-key support; automatic recovery from redo log in case of crash; Btree index; Clustered table; different file format (internal); data compression. 3.  emory M •  No transaction; no version control; no Geospatial support; no foreign-key; full Table lock; •  Data cached in memory; Btree index; Hash index; Storage limit is the available RAM.20 1 © 2010/2011 Pythian 3
  • 14. MySQL Storage engine more details 2/2 1.  MySQL Cluster •  No geospatial support; no foreign-key; no “Temporary” tables; partition only by [LINEAR] KEY; only the READ COMMITTED isolation level is supported; no partial roll- back (full or nothing); a Select on Blob or Text fields will create a READ LOCK on the table to guarantee consistency. •  Fully ACID; share nothing architecture; single point of failure; write scale by node- group; thread requests parallelization; and a lot more …20 1 © 2010/2011 Pythian 4
  • 15. MySQL Logs 1/2 What they are and how MySQL uses them. • General Log •  each SQL statement received from clients; connection/disconnection as well •  Write intensive to be used ONLY for checking issues • Binary log •  Contains the statements “events” that modify data structure and datasets •  Point in time recovery; Replication; Backup; can be (statement/mixed/row) • Relay log •  Is the local copy of the Slave; contains the same information of the Binlogs • Slow log • The Error Log •  Self explanatory in the latest MySQL can write to syslog20 1 © 2010/2011 Pythian 5
  • 16. MySQL Logs 2/2 What they are and how MySQL uses them. • Slow log •  Information related to SLOW QUERY •  Could be write intensive; long time and no index usage configurable •  Crucial for SQL review • The Error Log •  If not specify --log-error errors are written to stderr •  Warnings are written as well (log_warnings) to disable •  From MySQL 5.1 can also write to syslog20 1 © 2010/2011 Pythian 6
  • 17. MySQL Replication Replication topology, and when to use what. • Master -> Slave • Master <> Master • Master -> Multi slave • MySQL replication pro and cons •  Single thread •  Parallel replication20 •  Asynchronous 1 © 2010/2011 Pythian 7
  • 18. Scaling with MySQL Replication. •  caling for reads S •  Add slave(s) but … keep in mind PT = (ND + QT) * NL PT = Propagation Time ND = Network time delay QT = Query Execution Time NL = Number of Level •  caling for writes S •  Sharding or MySQL Cluster •  caling out vs. scaling up S •  Partition •  Spread the load in smaller chunk •  sing the right approach U •  Database dimension •  Activity (r/w)20 1 © 2010/2011 Pythian 8
  • 19. Partitioning 1/2 Use Partition to organize data Max number of partition per table !1024! Types of partitioning •  ANGE R •  Numeric range like (store Id; Year) less then “value” •  IST L •  Declared list of value (matching one in the list) •  OLUMNS C •  RANGE: List of a single column value or more (partition definition value list) evaluation left->right •  LIST: Declared list of value coming from one or more columns •  No DECIMAL, FLOAT,TIMESTAMP,TEXT,BLOB20 1 © 2010/2011 Pythian 9
  • 20. Partitioning 2/2 Types of partitioning (cont.) •  ASH H •  Calculate an hash value on the given value (also expression) then equally distribute the data •  EY K •  Calculate an hash value on Primary/Unique •  ubpartitioning S •  Works for LIST and RANGE Partitioned tables •  Subpartition only by HASH or KEY Partition cannot be done on table with: Full Text index ; Spatial columns20 2 © 2010/2011 Pythian 0
  • 21. MySQL programming 2/2 A few point about performance •  Not as good you would expect •  Optimize IF •  Recursive VS not recursive calculating Fibonacci numbers20 2 © 2010/2011 Pythian 1
  • 22. MySQL programming Using stored procedure (code for performance on prime numbers) CREATE PROCEDURE sp_nprimes(p_num int)PROCEDURE N_PRIMES ( p_num NUMBER) BEGIN IS DECLARE i INT; i INT; DECLARE j INT; j INT; DECLARE nprimes INT; nprimes INT; DECLARE isprime INT; isprime INT;BEGIN SET i=2; i:=2; SET nprimes=0; nprimes:=0; <<main_loop>> main_loop: WHILE (i<p_num) LOOP WHILE (i<p_num) do isprime:=1; SET isprime=1; j:=2; SET j=2; <<divisor_loop>> divisor_loop: WHILE (j<i) LOOP WHILE (j<i) DO IF (MOD(i,j)=0) THEN IF (MOD(i,j)=0) THEN isprime:=0; SET isprime=0; EXIT divisor_loop; LEAVE divisor_loop; END IF; END IF; j:=j+1; SET j=j+1; END LOOP ; END WHILE ; IF (isprime=1) THEN IF (isprime=1) THEN nprimes:=nprimes+1; SET nprimes=nprimes+1; END IF; END IF; i:=i+1; SET i=i+1; END LOOP; END WHILE; dbms_output.put_line(nprimes|| prime numbers SELECT CONCAT(nprimes, prime numbers less less than ||p_num); than ,p_num);END; END;20 2 © 2010/2011 Pythian 2
  • 23. MySQL programming Using Store procedure (code for Fibonacci test)Recursive Not Recursive CREATE PROCEDURE nonrec_fib(n INT,OUT out_fib INT)CREATE PROCEDURE rec_fib(n INT,OUT out_fib BEGIN INT) DECLARE m INT default 0;BEGIN DECLARE k INT DEFAULT 1; DECLARE n_1 INT; DECLARE i INT; DECLARE n_2 INT; DECLARE tmp INT; IF (n=0) THEN SET m=0; SET out_fib=0; SET k=1; ELSEIF (n=1) then SET i=1; SET out_fib=1; ELSE WHILE (i<=n) DO CALL rec_fib(n-1,n_1); SET tmp=m+k; CALL rec_fib(n-2,n_2); SET m=k; SET out_fib=(n_1 + n_2); SET k=tmp; END IF; SET i=i+1;END END WHILE; SET out_fib=m; END 20 2 © 2010/2011 Pythian 3
  • 24. MySQL programming 1/2 •  Using Store procedure • Programming is real at a basic level; no packages etc… • Triggers and function could leads to unexpected results by Storage engine •  Real status about store procedure • Triggers; Functions; Store procedure • Using SELECT INTO is fine for single-row queries; CURSORS; Unbound result set (return result set to calling application); Non SELECT actions (update, insert, delete); Internal CALL to other Store Procedure; few info about performance •  Error handling available from 5.5 onwards with SIGNAL and RESIGNAL20 2 © 2010/2011 Pythian 4
  • 25. MySQL HA solution How many nines do you need? 9 0. 0 0 0 % (36 days) MySQL Replication 9 9. 0 0 0 % (8 hours) Linux Heartbeat with DRBD 9 9. 0 0 0 % (8 hours) Linux Heartbeat with Shared Storage (Active/Passive) 9 9. 0 0 0 % (8 hours) Linux Heartbeat with Shared Storage (Active/Active) 9 9. 9 0 0 % (52 minutes) Linux Heartbeat with DRBD and Replication 9 9. 9 0 0 % (52 minutes) Linux Heartbeat with Shared Storage and Replication 9 9. 9 9 9 % (5 minutes) MySQL Cluster 9 9. 9 9 9 % (5 minutes) MySQL Cluster & Replication 9 9. 9 9 9 % (5 minutes) MySQL Cluster Carrier Grade Edition [Time is possible outage per year]20 2 © 2010/2011 Pythian 5
  • 26. MySQL Backup •  Logical MySQL Backup •  mysqldump •  export •  Physical MySQL backup •  LVM Snapshot •  ZFS snapshot •  File copy •  Hot Backup (xtrabackup) •  Incremental backup –  Xtrabackup –  binlogs20 2 © 2010/2011 Pythian 6
  • 27. Managing MySQL MySQL tools •  lient application C •  Non GUI •  mysql — The MySQL Command-Line Tool •  mysqladmin — Client for Administering a MySQL Server •  mysqlcheck — A Table Maintenance Program •  mysqldump — A Database Backup Program •  mysqlimport — A Data Import Program •  mysqlshow — Display Database, Table, and Column Information •  UI G •  Workbench; Navicat; SQLyog … Google20 2 © 2010/2011 Pythian 7
  • 28. Managing MySQL Administration tools •  Non GUI •  innochecksum — Offline InnoDB File Checksum Utility •  myisam_ftdump — Display Full-Text Index information •  myisamchk — MyISAM Table-Maintenance Utility •  myisampack — Generate Compressed, Read-Only MyISAM Tables •  mysqlaccess — Client for Checking Access Privileges •  mysqlbinlog — Utility for Processing Binary Log Files •  mysqldumpslow — Summarize Slow Query Log Files •  mysqlhotcopy — A Database Backup Program (Archive MyISAM) •  perror — Explain Error Codes20 2 © 2010/2011 Pythian 8
  • 29. Monitoring MySQL Status •  MySQL enterprise monitor •  Historical monitor •  Cacti •  MONyog •  Live monitoring •  What we do at Pythian   Avail software for monitoring of paging/alerts and daily pro-active checks •  Scripts •  Nagios plugin •  Issue is: define the correct parameters to monitor20 2 © 2010/2011 Pythian 9
  • 30. Use the right tool for the right use What MySQL is good for •  TLP O •  mall/mid size datasets (per instance) say less then 10Tb S •  pplications using many simultaneous connections A What is better to avoid •  ata warehouse D •  pplications requiring heavy usage of Stored Procedure A •  pplications requiring Hierarchical query (connect by prior etc.) A •  atasets that could not scale by SHARD D20 3 © 2010/2011 Pythian 0
  • 31. Q & A Thank you! tusa@pythian.com http://www.pythian.com/ http://www.pythian.com/news/ Interested in joining our elite team of trusted database expert? Pythian is hiring. More details at: http://www.pythian.com/about/careers/job- listings/20 3 © 2010/2011 Pythian 1