May 24, 2012

Post: MySQL File System Fragmentation Benchmarks

… and Innodb tables on ext3 filesystem. Here is what I found: The fragmentation we speak in this article is filesystem fragmentation or internal table fragmentation… suffers worse than InnodbInnodb extent allocation works (perhaps would be good option for MyISAM as well) – Innodb suffers fragmentation less if it stores…

Post: Heikki Tuuri Innodb answers - Part I

…. The first 32 pages of a segment are allocated from ‘fragment extents’ where any individual page can be allocated to whatever… has been done on it by Inaam. Q19: INNODB uses it’s own internal buffer pool but it’s in conflict with the Linux kernel’s buffer pool. In high load situations where INNODB

Post: Innodb Double Write

… be internally consistent. It does not matter which page version it is – it could be “current” version in which case Innodb will… just between their execution. Reasons for splitting could be file fragmentation – most file systems use 4K block sizes by default so 16K could use more than one fragment. Also if software RAID is used page may come on…

Post: MySQL Binaries Percona build10

… | innodb_check_defrag.patch | Session status to check fragmentation of the last InnoDB scan | 1.0 | Percona | GPL | The names are Innodb…) | | innodb_show_hashed_memory.patch | Adds additional information of InnoDB internal hash table memories in SHOW INNODB STATUS | 1.0 | Percona | GPL | | | innodb

Post: Percona build7 with latest patches

… | innodb_check_defrag.patch | Session status to check fragmentation of the last InnoDB scan | 1.0 | Percona | GPL | The names are Innodb…) | | innodb_show_hashed_memory.patch | Adds additional information of InnoDB internal hash table memories in SHOW INNODB STATUS | 1.0 | Percona | GPL | | | innodb

Post: Read Buffers, mmap, malloc and MySQL Performance

… required size, which can get expensive if virtual memory gets fragmented. A while ago I measured over 10 times slow down over time as memory becomes fragmented with 50.000+ of memory areas mapped. As the gap… for Innodb Buffer Pool and Key Buffer but could be used for other large allocations. Finally this is yet another reasons internal

Comment: Falcon Storage Engine Design Review

… it in current Limits section though. Isolation Modes: Innodb, Oracle, PostgreSQL also support MVCC but frequently offer …fit to the old one any more but gets fragmented now right ? Regarding real world applications – very significant …, so there is no insight so far on internal processes which are …

Post: Falcon Storage Engine Design Review

…, in fact this is what you can get in Innodb (by using its internal hidden primary key) but this functionality is not… may end up in non-recoverable stage. This is why Innodb has “innodb double write buffer”. Jim does not believe this is… I have not found much information about is regarding handling fragmentation – what happens on row updates, are they stored in the…

Comment: InnoDB memory allocation, ulimit, and OpenSUSE

… possible value that would allow mysqld to start without disabling InnoDB or plain crashing because that is a dangerous game. malloc… the thread stacks. Some for other internal needs of MySQL. Some waste from memory space fragmentation. It would all add up eventually…