June 18, 2013

Post: MySQL Query Patterns, Optimized - Webinar questions followup

June 3, 2013 By 2 Comments

… 47000 and 50000 with no movies, but your random number generator picks values in that range with equal frequency as any… is that it requires storing another column, and reinitializing the sequence after making certain insert/update/delete operations.  If you have…

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Post: Stored Function to generate Sequences

April 2, 2008 By 17 Comments

…. Finally your own sequences allow you to generate multiple sequence values on demand with single statement for one or more sequences, which also can… this sequence generation requires serialization, though it is short term but it may still become the bottleneck for application with high sequence use…

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Comment: Stored Function to generate Sequences

May 8, 2008 By 17 Comments

[...] Stored Function to generate Sequences | MySQL Performance Blog – You could combine this with an INSERT trigger and get even more auto_increment like functionality. Tags: database mysql sequence [...]

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Comment: Returning to InnoDB scalability

August 7, 2006 By 42 Comments

… =================================================== =================MySQL error log=================== 060804 20:56:56 InnoDB: Started; log sequence number 45 3475747758 060804 20:56:56 [Note] /opt/mysql… assertion: (buf_pool->flush_list).count > 0 InnoDB: We intentionally generate a memory trap. InnoDB: Submit a detailed bug report to… on checkpoint at InnoDB: log sequence number 45 3501426558. InnoDB: Doing recovery: scanned up to log sequence number 45 3501428038 060804 21…

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Post: InnoDB Full-text Search in MySQL 5.6 (part 1)

February 26, 2013 By 1 Comment

… it, and then I create one, the following warning is generated: mysql> alter table dir_test_innodb ADD FULLTEXT KEY (full… for the underlying table, or it can be a sequence value generated by InnoDB when the table does not contain a suitable… unless you also do something to provide some sort of sequence value for that column, whether as an auto_increment value…

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Post: To UUID or not to UUID ?

March 13, 2007 By 28 Comments

… but use certain partitioned sequences, for example you can have 256 growing sequences (with high byte used for sequence number) which will have… auto_increment and which could be used to have values generated at same point in time physically local in BTREE index…

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Post: Recovery after DROP & CREATE

August 22, 2012 By 1 Comment

… the same name. This is because  mysqldump in many cases generates the “DROP TABLE” instruction before the “CREATE TABLE”: DROP TABLE… length is 12 bytes. So, if we ever meet byte sequence 0×00 0x0C sakila/actor 0×01 0×08 the next eight bytes… approach is applicable for SYS_INDEXES. We can search for sequence 0×00 0×08
0×01 0×08 and next 8 bytes…

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Post: Recovery deleted ibdata1

August 10, 2012 By 9 Comments

… I will delete /var/lib/mysql/ib* files, while sysbench generates read/write activity: Screen0: root@localhost:~# sysbench –num-threads=16… age. The checkpoint age is a difference between current log sequence number and last checkpoint in “SHOW ENGINE INNODB STATUS” output… checkpoint age is zero, all pages are flushed: — LOG — Log sequence number 363096003 Log flushed up to 363096003 Last checkpoint at…

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Comment: ORDER BY ... LIMIT Performance Optimization

September 2, 2006 By 100 Comments

… approach would be to pre-create sequence of ordered values and use it. For example generate 1.000.000 of random rows… is enough to run in circles for other you can generate more rows as soon as they are used. The good…

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Comment: Stored Function to generate Sequences

April 3, 2008 By 17 Comments

kL, even with a sequence generator stored in MyISAM you would not see the same number in different threads.

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