MySQL 优化
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MySQL 优化

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MySQL 优化

MySQL 优化

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MySQL 优化 MySQL 优化 Presentation Transcript

  • MySQL Optimization (A couple of different ways.) Morgan Tocker morgan@percona.com 1 Monday, March 7, 2011
  • ★ InnoDB? ★ MyISAM? ★ XtraDB? ★ MySQL 4.x? ★ MySQL 5.0.x? ★ MySQL 5.1? ★ MySQL 5.5? ★ Something else? 2 Show of Hands Monday, March 7, 2011
  • About this presentation ★ Q: “Would you like to talk about MySQL optimization?” ★ A: Sure. ★ Optimization can be made at many levels. ★ I’m going to show 2-3 parts of the puzzle: ✦ Query Optimization. ✦ How InnoDB works. ✦ (Time Permitting) Our work at Percona on improving MySQL. 3 Monday, March 7, 2011
  • It all starts with EXPLAIN ★ Bookmark this manual page: http://dev.mysql.com/doc/refman/5.1/en/using- explain.html ★ It is the best source for anyone getting started. 4 Monday, March 7, 2011
  • Examples come from: ★ IMDB database loaded into InnoDB tables (~5G). ★ Download it and import it for yourself using imdbpy2sql.py: http://imdbpy.sourceforge.net/ 5 Monday, March 7, 2011
  • First Example 6 Monday, March 7, 2011
  • Find the Title Bambi 7 ALL means tablescan In this case a sort is required because of the order by Anticipated number of rows to be examined Additional filtering may be possible before passing to sort. 3.09s Monday, March 7, 2011
  • Aha! Now add an index: 8 Monday, March 7, 2011
  • We must revisit... 9 Using = for comparison, but not primary key lookup. Size of the index used (in bytes) Anticipated number of rows to be examined dropped considerably. Identified title as a candidate index, chose to use it. 0.00s Monday, March 7, 2011
  • Other ways of accessing 10 Better type of ‘const’. We can stop when we find one row. 0.00s At most one matching row. In InnoDB the primary key is often much faster than all other keys. Monday, March 7, 2011
  • And.. 11 Ignore the time with EXPLAIN. Only look at the time for a query. Type is range. BETWEEN, IN() and < > are also ranges. Number of rows to be examined has increased - we are not specific enough. 0.00s Monday, March 7, 2011
  • Why’s that a range? ★ We're looking for titles between BambA and BambZ* ★ When we say index in MySQL, we mean trees. ✦ That is, B-Tree/B+Tree/T-Tree. ✦ Pretend they're all the same (for simplification). ✦ There's no radically different indexing methods in MySQL unless you play storage engine Bingo**. 12 * In reality the range is a little wider ** The memory storage engine supports hash indexes Monday, March 7, 2011
  • What’s that? 13 Monday, March 7, 2011
  • Could this be a range? 14 3.2s Monday, March 7, 2011
  • No, we can’t traverse. 15 Do we head left or right here? Monday, March 7, 2011
  • LIKE ‘Z%’ 16 0.05s Monday, March 7, 2011
  • LIKE ‘T%’ 17 3.13s Monday, March 7, 2011
  • LIKE ‘The %’ 18 3.07s Monday, March 7, 2011
  • MySQL is (reasonably) smart. ★ It dynamically samples the data to choose which is the better choice - or in some cases uses static statistics*. ★ This helps the optimizer choose: ✦ Which indexes will be useful. ✦ Which indexes should be avoided. ✦ Which is the better index when there is more than one. 19 * To refresh statistics run ANALYZE TABLE table_name; Monday, March 7, 2011
  • Why avoid indexes? ★ B-Trees work like humans search a phone book; ✦ Use an index if you want just a few rows. ✦ Scan cover-to-cover if you want a large percentage. 20 Monday, March 7, 2011
  • ★ We benchmarked this on a different schema: Why avoid indexes (cont.) 21 Table scan has a relatively fixed cost (red line). The index has completely different effectiveness depending on how much it can filter. Hopefully MySQL switches at the right point. Monday, March 7, 2011
  • What you should take away: ★ Data is absolutely critical. ✦ Development environments should contain sample data exported from production systems. ★ Input values are absolutely critical. ✦ Between two seemingly identical queries, execution plans may be very different. 22 See also: http://www.mysqlperformanceblog.com /2009/10/16/how-not-to-find-unused-indexes/ Monday, March 7, 2011
  • Improve this Query 23 3.41s This number of rows is a guess. It keeps changing between examples. Monday, March 7, 2011
  • We’re Spoiled for Choice. 24 Monday, March 7, 2011
  • Index on production_year 25 3.53s Monday, March 7, 2011
  • Might work if... 26 0.92s Monday, March 7, 2011
  • Index on title(50) 27 0.02s Monday, March 7, 2011
  • Comparing the two: 28 ★ mysql> EXPLAIN SELECT * from title WHERE title = 'Pilot' AND production_year BETWEEN 2006 and 2009G Monday, March 7, 2011
  • Composite Indexes. ★ What is better? ✦ INDEX py_t (production_year, title) ✦ INDEX t_py (title, production_year) 29 Monday, March 7, 2011
  • Index on py_t 30 0.02s http://www.mysqlperformanceblog.com/2010/01/09/getting-around- optimizer-limitations-with-an-in-list/ Monday, March 7, 2011
  • Index on t_py 31 0.00s Monday, March 7, 2011
  • Recommendations ★ Index over multiple columns if it can improve filtering. i.e. ✦ GOOD: Only some pilots made between 2006-2009. ✦ BAD: All pilots made between 2006-2009. 32 Monday, March 7, 2011
  • Recommendations (cont.) ★ Don't know what order to specify the columns? ✦ RULE: Think how to filter the fastest. Use that order left to right. ✦ EXCEPTION: If there's a range (><, BETWEEN, %). Those always go to the RIGHT. 33 http://www.mysqlperformanceblog.com/2010/01/09/getting-around- optimizer-limitations-with-an-in-list/ Monday, March 7, 2011
  • Query Tuning Monday, March 7, 2011
  • How InnoDB Works Monday, March 7, 2011
  • “Numbers everyone should know” 36 L1 cache reference 0.5 ns Branch mispredict 5 ns L2 cache reference 7 ns Mutex lock/unlock 25 ns Main memory reference 100 ns Compress 1K bytes with Zippy 3,000 ns Send 2K bytes over 1 Gbps network 20,000 ns Read 1 MB sequentially from memory 250,000 ns Round trip within same datacenter 500,000 ns Disk seek 10,000,000 ns Read 1 MB sequentially from disk 20,000,000 ns Send packet CA->Netherlands->CA 150,000,000 ns See: http://www.linux-mag.com/cache/7589/1.html and Google http:// www.cs.cornell.edu/projects/ladis2009/talks/dean-keynote-ladis2009.pdf Monday, March 7, 2011
  • About Disks. ★ 10,000,000 ns = 10ms = 100 operations/second. ✦ This is about the average for a 7200RPM drive. ★ The actual time has dramatic variation. ✦ The variation is because disks are mechanical. ✦ We can much write faster sequentially than randomly. 37 Monday, March 7, 2011
  • [default] Everything is buffered! ★ When you write to a file, here’s what happens in the Operating System: 38 Block 9, 10, 1, 4, 200, 5. Block 1, 4, 5, 9, 10, 200 What happens to this buffer if we loose power? Monday, March 7, 2011
  • The OS provides a way! ★ $ man fsync 39 Synopsis #include <unistd.h> int fsync(int fd); int fdatasync(int fd); Description fsync() transfers ("flushes") all modified in-core data of (i.e., modified buffer cache pages for) the file referred to by the file descriptor fd to the disk device (or other permanent storage device) where that file resides. The call blocks until the device reports that the transfer has completed. It also flushes metadata information associated with the file (see stat(2)). Hint: MyISAM just writes to the OS buffer and has no durability. http://thunk.org/tytso/blog/2009/03/15/dont-fear-the-fsync/ Monday, March 7, 2011
  • Knowing this: ★ InnoDB wants to try and reduce random IO. ★ It can not (safely) rely on the operating system’s write buffering and be ACID compliant. ✦ .. and InnoDB algorithms have to compensate. 40 Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (High Level) Log Files 41 SELECT * FROM City WHERE CountryCode=ʼAUSʼ Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (cont.) 42 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Why don’t we update? ★ This is an optimization! ✦ The log file IO is sequential and much cheaper than live updates. ✦ The IO for the eventual updates to the tablespace can be optimized as well. ★ Provided that you saved enough to recover, this shouldn’t matter should it? 43 Monday, March 7, 2011
  • More on Logs... ★ Logs are only used during recovery. ✦ Not even read when we need to write down dirty pages! ★ To figure out which pages need to be evicted we have two lists - the flush list and the LRU. ★ Log activities are all assigned a LSN (log sequence number). 44 Log Files Monday, March 7, 2011
  • Log Files, Checkpoints, etc. ★ Most database systems work this way: ✦ In Oracle the transaction logs are called “Redo Logs”. ★ The background process of syncing dirty pages is normally referred to as a “Checkpoint”. ★ InnoDB has fuzzy checkpointing. 45 Monday, March 7, 2011
  • Log Writing ★ You can change increase innodb_log_file_size. This will allow InnoDB to “smooth out” background IO for longer. ✦ Tip: Optionally you could change innodb_log_files_in_group as well. Be aware that your effective log file is innodb_log_file_size * innodb_log_files_in_group 46 Monday, March 7, 2011
  • Log Writing (cont.) ★ You can also change innodb_flush_log_at_trx_commit to 0 or 2 to reduce the durability requirements of this write. ✦ Requires less flushing - particularly helpful on systems without writeback caches! ★ innodb_log_buffer_size may also help buffer changes for longer before writing to the logs. ✦ Very workload dependent - tends to be more helpful for writing big TEXT/BLOB changes. 47 Monday, March 7, 2011
  • In summary ★ On commit, the log has to be flushed to guarantee changes. ✦ Nothing else has to be done. ★ What visibility do we have into these operations? ★ How do we decide how much background work to do per second? ★ What happens if we fall behind in background work? 48 Monday, March 7, 2011
  • Enhancements via Percona Monday, March 7, 2011
  • Terminology 50 Oracle Product License Percona Equivalent Product License MySQL Server GPL Percona Server GPL The InnoDB Storage Engine (Plugin edition) GPL The XtraDB Storage Engine GPL InnoDB Hot Backup Commercial XtraBackup GPL (GPL = Completely free for you to use. Support not included.) Monday, March 7, 2011
  • Performance Improvements 51 Improved Buffer Pool Scalability Improved IO Path + adaptive checkpointing Improved Rollback Segment Scalability*Separate purge thread Data dictionary memory consumption controls Increased number of undo slots* Faster page checksums* Support for different page sizes* * Changes on disk format (not backwards compatible) Insert buffer controls Completely disable the query cache. Remove excess fcntl calls Per session configuration of innodb_flush_log_at_trx_commit Separate location of double write buffer* Strip comments before using query cache Transaction logs larger than 4G supported. Monday, March 7, 2011
  • Improved Buffer Pool Scalability ★ Additional patches to what is already available in the InnoDB Plugin. ✦ Splits the buffer pool mutex into smaller mutexes: • Flush list mutex • LRU mutex • Free mutex • hash mutex 52 Monday, March 7, 2011
  • Data Dictionary control ★ Once an InnoDB table is opened it is never freed from the in-memory data dictionary (which is unlimited in size). ★ XtraDB introduces: ✦ --innodb_dict_size_limit - a configuration item in bytes. ✦ innodb_dict_tables - a status variable for number entries in the cache. 53 Monday, March 7, 2011
  • Undo Slots ★ In the built-in InnoDB, the number of undo slots is limited to 1024. ✦ This means the number of open transactions is limited to 1023. See: http://bugs.mysql.com/bug.php?id=26590 ✦ Some statements require 2 undo slots. ★ In XtraDB, this is expanded to 4072 with -- innodb_extra_undoslots=1. 54 Warning: This is binary format incompatible! Monday, March 7, 2011
  • Rollback Segments ★ In XtraDB, it’s also possible to have more than one rollback segment. ✦ Each segment contains undo slots. ★ Configuration is --innodb-extra-rsegments=N ★ This has the added effect of reducing mutex contention on the rollback segment: ✦ “Mutex at 0×1b3e3e78 created file trx/trx0rseg.c line 167″ 55 http://www.percona.com/docs/wiki/percona- xtradb:patch:innodb_extra_rseg http://www.mysqlperformanceblog.com/2009/10/14/tuning- for-heavy-writing-workloads/ Warning: This is binary format incompatible! Monday, March 7, 2011
  • Fast Checksums ★ The InnoDB page checksum computation is slower than it needs to be. ★ XtraDB has the option to use a faster checksum format. 56 Warning: This is binary format incompatible! Monday, March 7, 2011
  • Different Page Sizes ★ XtraDB now has support for different page sizes - 4K, 8K, 16K. 57 Warning: This is binary format incompatible! Monday, March 7, 2011
  • Separate Purge Thread ★ Cleans up a long history list length faster: 58 See: http://www.mysqlperformanceblog.com/2009/10/14/ tuning-for-heavy-writing-workloads/ Monday, March 7, 2011
  • Usability Enhancements 59 Show contents of the buffer pool Import / export of innodb_file_per_table tables Import / export of buffer pool contents Transactional Replication Better handling of corrupted tables Store buffer pool in shared memory segment Save index statistics between restarts Advise in processlist when waiting on Query cache mutex. Improved slow query log User / Index / Table statistics Disable automatic statistics regeneration Show data dictionary Deadlock counter Show Temporary Tables Log connection errors Retain query response time distribution. Monday, March 7, 2011
  • Show Buffer Pool Contents 60 mysql> SELECT d.*,round(100*cnt*16384/(data_length+index_length),2) fit FROM (SELECT schema_name,table_name,count(*) cnt,sum(dirty),sum(hashed)  FROM INNODB_BUFFER_POOL_PAGES_INDEX GROUP BY schema_name,table_name ORDER BY cnt DESC LIMIT 20) d JOIN TABLES ON (TABLES.table_schema=d.schema_name AND TABLES.table_name=d.table_name); +-------------+---------------------+---------+------------+-------------+--------+ | schema_name | table_name          | cnt     | sum(dirty) | sum(hashed) | fit    | +-------------+---------------------+---------+------------+-------------+--------+ | db          | table1              | 1699133 |      13296 |      385841 |  87.49 | | db          | table2              | 1173272 |      17399 |       11099 |  98.42 | | db          | table3              |  916641 |       7849 |       15316 |  94.77 | | db          | table4              |   86999 |       1555 |       75554 |  87.42 | | db          | table5              |   32701 |       7997 |       30082 |  91.61 | | db          | table6              |   31990 |       4495 |       25681 | 102.97 | | db          | table7              |       1 |          0 |           0 | 100.00 | +-------------+---------------------+---------+------------+-------------+--------+ 7 rows in set (26.45 sec) Source: http://www.mysqlperformanceblog.com/ 2010/03/26/tables-fit-buffer-poo/ * Command may differ slightly between versions. Monday, March 7, 2011
  • Save Buffer Pool Contents ★ Export the contents of the buffer pool to a file called ‘ib_lru_dump’ in the data directory: ✦ SELECT * FROM information_schema.XTRADB_ADMIN_COMMAND /*! XTRA_LRU_DUMP*/; ★ Restored ib_lru_dump: ✦ SELECT * FROM information_schema.XTRADB_ADMIN_COMMAND /*! XTRA_LRU_RESTORE*/; 61 Note: Not the actual contents - it takes 8 bytes to remember the address of a 16K page. Monday, March 7, 2011
  • Import/Export tables ★ Because --innodb-file-per-table still has information (data dictionary, undo) in the global tablespace you can’t just back it up by itself. ★ With a new setting, --innodb_expand_import=1, this is no longer the case. ★ Tip: The import/export still has to be done with XtraBackup. Documentation available here: http://www.percona.com/docs/wiki/percona-xtradb:patch:innodb_expand_import 62 Monday, March 7, 2011
  • The Slow Query Log 63 $ mysql -e “SET GLOBAL log_slow_verbosity = ‘full’;” $ tail /var/log/mysql.slow .. # Time: 100924 13:58:47 # User@Host: root[root] @ localhost [] # Thread_id: 10 Schema: imdb Last_errno: 0 Killed: 0 # Query_time: 399.563977 Lock_time: 0.000110 Rows_sent: 1 Rows_examined: 46313608 Rows_affected: 0 Rows_read: 1 # Bytes_sent: 131 Tmp_tables: 1 Tmp_disk_tables: 1 Tmp_table_sizes: 25194923 # InnoDB_trx_id: 1403 # QC_Hit: No Full_scan: Yes Full_join: No Tmp_table: Yes Tmp_table_on_disk: Yes # Filesort: Yes Filesort_on_disk: Yes Merge_passes: 5 # InnoDB_IO_r_ops: 1064749 InnoDB_IO_r_bytes: 17444847616 InnoDB_IO_r_wait: 26.935662 # InnoDB_rec_lock_wait: 0.000000 InnoDB_queue_wait: 0.000000 # InnoDB_pages_distinct: 65329 SET timestamp=1285336727; select STRAIGHT_JOIN count(*) as c, person_id FROM cast_info FORCE INDEX(person_id) INNER JOIN title ON (cast_info.movie_id=title.id) WHERE title.kind_id = 1 GROUP BY cast_info.person_id ORDER by c DESC LIMIT 1; $ tail /var/log/mysql.slow .. # Time: 100924 13:58:47 # User@Host: root[root] @ localhost [] # Query_time: 399.563977 Lock_time: 0.000110 Rows_sent: 1 Rows_examined: 46313608 SET timestamp=1285336727; select STRAIGHT_JOIN count(*) as c, person_id FROM cast_info FORCE INDEX(person_id) INNER JOIN title ON (cast_info.movie_id=title.id) WHERE title.kind_id = 1 GROUP BY cast_info.person_id ORDER by c DESC LIMIT 1; MySQL Server Percona Server Monday, March 7, 2011
  • User Statistics 64 mysql> SET GLOBAL userstat_running = 1; mysql> SELECT DISTINCT s.TABLE_SCHEMA, s.TABLE_NAME, s.INDEX_NAME FROM information_schema.statistics `s` LEFT JOIN information_schema.index_statistics IS ON (s.TABLE_SCHEMA = IS.TABLE_SCHEMA AND s.TABLE_NAME=IS.TABLE_NAME AND s.INDEX_NAME=IS.INDEX_NAME) WHERE IS.TABLE_SCHEMA IS NULL; +--------------+---------------------------+-----------------+ | TABLE_SCHEMA | TABLE_NAME                | INDEX_NAME      | +--------------+---------------------------+-----------------+ | art100       | article100                | ext_key         | | art100       | article100                | site_id         | | art100       | article100                | hash            | | art100       | article100                | forum_id_2      | | art100       | article100                | published       | | art100       | article100                | inserted        | | art100       | article100                | site_id_2       | | art100       | author100                 | PRIMARY         | | art100       | author100                 | site_id         | ... +--------------+---------------------------+-----------------+ 1150 rows IN SET (1 min 44.23 sec) MySQL Server Percona Server ( Not Possible ) Monday, March 7, 2011
  • (Related) Xtrabackup Features ★ Report on fragmentation of indexes: ★ $ xtrabackup --stats --tables=art.link* -- datadir=/mnt/data/mysql/ ... table: art/link_out104, index: PRIMARY, space id: 12, root page 3 leaf pages: recs=25958413, pages=497839, data=7492026403 bytes, data/pages=91% ... 65 http://www.mysqlperformanceblog.com/2009/09/14/statistics- of-innodb-tables-and-indexes-available-in-xtrabackup/ Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. Increase the size of the log files (innodb_log_file_size and innodb_log_files_in_group) Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. Set innodb_flush_log_at_trx_commit=2 if durability is not as important. Increase the size of the log files (innodb_log_file_size and innodb_log_files_in_group) Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. Typically use innodb_flush_method=O_DIRECT if using a Hardware RAID controller. Set innodb_flush_log_at_trx_commit=2 if durability is not as important. Increase the size of the log files (innodb_log_file_size and innodb_log_files_in_group) Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. (Possibly) Move the log files to separate spindles (sequential IO) Typically use innodb_flush_method=O_DIRECT if using a Hardware RAID controller. Set innodb_flush_log_at_trx_commit=2 if durability is not as important. Increase the size of the log files (innodb_log_file_size and innodb_log_files_in_group) Monday, March 7, 2011
  • Basic Operation (again.) 66 Log Files UPDATE City SET name = 'Morgansville' WHERE name = 'Brisbane' AND CountryCode='AUS' 01010 Buffer Pool Tablespace Set innodb_buffer_pool_size to “50-80%” of memory. (Possibly) Move the log files to separate spindles (sequential IO) Typically use innodb_flush_method=O_DIRECT if using a Hardware RAID controller. Set innodb_flush_log_at_trx_commit=2 if durability is not as important. If innodb_log_waits > 0 the buffer being filled (innodb_log_buffer_size) before writing to the log files may be too small. Increase the size of the log files (innodb_log_file_size and innodb_log_files_in_group) Monday, March 7, 2011
  • The End. ★ Questions? 67 Monday, March 7, 2011