manual.texi Added a note on table defragmenting and a sentence on InnoDB speed

concurrency. There is not need for lock escalation in InnoDB,

because row level locks in InnoDB fit in very small space.

InnoDB has been designed for maximum performance when processing

large data volumes. Its CPU efficiency is probably not

matched by any other disk-based relational database engine.

Technically, InnoDB is a database backend placed under @strong{MySQL}. InnoDB

has its own buffer pool for caching data and indexes in main

memory. InnoDB stores its tables and indexes in a tablespace, which

purge operation after they are no longer needed in transaction rollback or

consistent read.

@subsubsection Defragmenting a table

If there are random insertions or deletions

in the indexes of a table, the indexes

may become fragmented. By this we mean that the physical ordering

of the index pages on the disk is not close to the alphabetical ordering

of the records on the pages. It can speed up index scans if you

periodically use @code{mysqldump} to dump the table to

a text file, drop the table, and reload it from the dump.

Note that if the insertions to and index are always ascending and

records are deleted only from the end, then the the file space management

algorithm of InnoDB guarantees that fragmentation in the index will

not occur.

@node Error handling, InnoDB restrictions, File space management, InnoDB

@subsection Error handling