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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
__dbf_set
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
Phrases
RDF data
Remote SQL Data Source
Replication
SOAP
SQL
String
Transaction
Type Mapping
UDDI
User Defined Types & The CLR
VAD
Virtuoso Java PL API
Virtuoso Server Extension Interface (VSEI)
Web & Internet
XML
XPATH & XQUERY

Functions Index

checkpoint_interval

Configure database checkpointing
integer checkpoint_interval (in minutes 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.

Parameters
minutes – integer number of minutes between checkpoints.
Return Types

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

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