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Preface

Virtuoso Functions Guide

Administration
db.dba.vacuum
user_change_password
user_create
user_drop
user_get_option
user_grant_role
user_revoke_role
user_role_create
user_role_drop
user_set_option
user_set_qualifier
cfg_item_count
cfg_item_name
cfg_item_value
cfg_section_count
cfg_section_name
cfg_write
checkpoint_interval
disconnect_user
fk_check_input_value...
key_estimate
log_enable
log_text
prof_enable
prof_sample
server_root
status
sys_lockdown
sys_stat
system
trace_status
user_set_password
virtuoso_ini_path
Aggregate Functions
Array Manipulation
BPEL APIs
Backup
Compression
Cursor
Date & Time Manipulation
Debug
Dictionary Manipulation
Encoding & Decoding
File Manipulation
Free Text
Hashing / Cryptographic
LDAP
Locale
Mail
Miscellaneous
Number
RDF data
Remote SQL Data Source
Replication
SOAP
SQL
String
Transaction
Type Mapping
UDDI
User Defined Types & The CLR
Virtuoso Java PL API
Virtuoso Server Extension Interface (VSEI)
Web Server & Internet
XML
XPATH & XQUERY

Functions Index

checkpoint_interval

Configure database checkpointing
integer checkpoint_interval (in minutes integer);
Parameters
minutes – integer number of minutes between checkpoints.
Return Types

Previous value of CheckpointInterval in the configuration file as an integer.

Description

This function changes the database checkpointing interval to the given value in minutes. It may also be used to disable checkpointing in two ways: By setting checkpoint interval to 0, the checkpoint will only be performed after roll forward upon database startup. A setting of -1 will disable all checkpointing. Main use for this function is to ensure a clean online backup of the database slices. Copying of the database may take long and checkpointing would modify those files in mid-copy, thus rendering the resulting copy unusable. In case the system should, for some reason or another, become unstable, it is sometimes better to disable checkpointing after a database restart to resume backing up from where it was left prior to a system crash. Disabling all checkpointing by giving checkpoint_interval the value of -1 will do just that.

The interval setting will be saved in the server configuration file as value of CheckpointInterval in section [Parameters], thus it will persist over consecutive server shutdown/restart cycles. A long checkpoint_interval setting will produce longer transaction logs, which in turn prolongs the time it takes for the database to perform a roll forward upon restart in case it was shut down without making a checkpoint.

Errors

Parameter data type checking errors

Examples
Simple examples

Disable checkpoints:

SQL> checkpoint_interval(-1);

Done. -- 25 msec.

Re-enable checkpoints (every 2 hrs):

SQL> checkpoint_interval(120);
callret
VARCHAR
______________________________________________________

-1

Done. -- 4 msec.
See Also

backup

CheckpointInterval setting in Configuring Server Startup Files section