Oracle 5.0 Reference Manual page 1269

InnoDB
Variable Scope
Dynamic Variable
This variable controls how to delay INSERT, UPDATE, and
operations are lagging (see
delays).
The transaction system maintains a list of transactions that have index records delete-
InnoDB
marked by or
UPDATE
exceeds
purge_lag
operation is delayed by
delay is computed in the beginning of a purge batch, every ten seconds. The operations are not
delayed if purge cannot run because of an old consistent read view that could see the rows to be
purged.
A typical setting for a problematic workload might be 1 million, assuming that transactions are small,
only 100 bytes in size, and it is permissible to have 100MB of unpurged
The lag value is displayed as the history list length in the
output. For example, if the output includes the following lines, the lag value is 20:
------------
TRANSACTIONS
------------
Trx id counter 0 290328385
Purge done for trx's n:o < 0 290315608 undo n:o < 0 17
History list length 20
•
innodb_mirrored_log_groups
The number of identical copies of log groups to keep for the database. This should be set to 1.
•
innodb_open_files
Command-Line Format
Option-File Format
Variable Name
Variable Scope
Dynamic Variable
This variable is relevant only if you use multiple tablespaces in InnoDB. It specifies the maximum
number of files that
.ibd
value is 300.
The file descriptors used for
by the
--open-files-limit
cache.
•
innodb_rollback_on_timeout
Version Introduced
Command-Line Format
Startup Options and System Variables
Global
Yes
Permitted Values
Type
numeric
Default
0
Range
0 .. 4294967295
Section 14.2.8, "InnoDB
operations. Let the length of this list be purge_lag. When
DELETE
innodb_max_purge_lag
((purge_lag/innodb_max_purge_lag
--innodb_open_files=#
innodb_open_files
innodb_open_files
Global
No
can keep open at one time. The minimum value is 10. The default
InnoDB
files are for
.ibd
[417] server option, and do not affect the operation of the table
5.0.32
--innodb_rollback_on_timeout
1249
operations when purge
DELETE
Multi-Versioning"). The default value 0 (no
[1248], each INSERT, UPDATE, and
[1248])×10)–5 milliseconds. The
TRANSACTIONS
only. They are independent of those specified
InnoDB
DELETE
table rows.
InnoDB
section of InnoDB Monitor