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slony_logshipper Tool

slony_logshipping— slony_logshippping daemon
slony_logshipper Tool
slony_logshipper is a tool designed to help apply logs. It runs as a daemon and scans the archive directory for new .SQL files
which it then applies to the target database. It can be run with three sorts of parameters:
Options, chosen from the following:
– h
display this help text and exit
– v
display program version and exit
– q
quiet mode
– l
cause running daemon to reopen its logfile
– r
cause running daemon to resume after error
– t
cause running daemon to enter smart shutdown mode
– T
cause running daemon to enter immediate shutdown mode
– c
destroy existing semaphore set and message queue (use with caution)
– f
stay in foreground (don’t daemonize)
– w
enter smart shutdown mode immediately

A specified log shipper configuration file
This configuration file consists of the following specifications:
Slony-I 2.2.6 Documentation 141 / 282

– logfile = ’./offline_logs/logshipper.log’;
Where the log shipper will leave messages.

– cluster name = ’T1’;
Cluster name

– destination database = ’dbname=slony_test3’;
Optional conninfo for the destination database. If given, the log shipper will connect to this database, and apply logs to it.

– archive dir = ’./offline_logs’;
The archive directory is required when running in “database-connected” mode to have a place to scan for missing (unapplied) archives.

– destination dir = ’./offline_result’;
If specified, the log shipper will write the results of data massaging into result logfiles in this directory.

– max archives = 3600;
This fights eventual resource leakage; the daemon will enter “smart shutdown” mode automatically after processing this many archives.

– ignore table "public"."history";
One may filter out single tables from log shipped replication

– ignore namespace "public";
One may filter out entire namespaces from log shipped replication

– rename namespace "public"."history" to "site_001"."history";
One may rename specific tables.

– rename namespace "public" to "site_001";
One may rename entire namespaces.

– post processing command = ’gzip -9 $inarchive’;
Pre- and post-processing commands are executed via system(3).
An “@” as the first character causes the exit code to be ignored. Otherwise, a nonzero exit code is treated as an error and
causes processing to abort.

Pre- and post-processing commands have two further special variables defined:
– $inarchive - indicating incoming archive filename

– $outnarchive - indicating outgoing archive filename

error command = ’ ( echo "archive=$inarchive" echo "error messages:" echo "$errortext" ) | mail -s "Slony log shipping
failed" postgres@localhost ’;
The error command indicates a command to execute upon encountering an error. All logging since the last successful completion of an archive is available in the $errortext variable.
In the example shown, this sends an email to the DBAs upon encountering an error.

Archive File Names
Each filename is added to the SystemV Message queue for processing by a slony_logshipper process.


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