rt-serializer - Serialize an RT database to disk
rt-validator --check && rt-serializer
This script is used to write out the entire RT database to disk, for later
import into a different RT instance. It requires that the data in the database
be self-consistent, in order to do so; please make sure that the database
being exported passes validation by rt-validator before attempting to use
While running, it will attempt to estimate the number of remaining objects to be
serialized; these estimates are pessimistic, and will be incorrect if
"--no-users", "--no-groups", or "--no-tickets"
If the controlling terminal is large enough (more than 25 columns high) and the
"gnuplot" program is installed, it will also show a textual graph of
the queue size over time.
- --directory name
- The name of the output directory to write data files to,
which should not exist yet; it is a fatal error if it does. Defaults to
"./ $Organization:Date/", where
$Organization is as set in RT_SiteConfig.pm,
and Date is today's date.
- Remove the output directory before starting.
- --size megabytes
- By default, "rt-serializer" chunks its output
into data files which are around 32Mb in size; this option is used to set
a different threshold size, in megabytes. Note that this is the threshold
after which it rotates to writing a new file, and is as such the lower
bound on the size of each output file.
- By default, all privileged users are serialized; passing
"--no-users" limits it to only those users which are referenced
by serialized tickets and history, and are thus necessary for internal
- By default, all groups are serialized; passing
"--no-groups" limits it to only system-internal groups, which
are needed for internal consistency.
- By default, all tickets, including deleted tickets, are
serialized; passing "--no-deleted" skips deleted tickets during
- No scrips or templates are serialized by default; this
option forces all scrips and templates to be serialized.
- No ACLs are serialized by default; this option forces all
ACLs to be serialized.
- Skip serialization of all ticket data.
- Takes a list of queue IDs or names separated by commas.
When provided, only that set of queues (and the tickets in them) will be
- Takes a list of custom field IDs or names separated by
commas. When provided, only that set of custom fields will be
- Replace links to local records which are not being migrated
with hyperlinks. The hyperlinks will use the serializing RT's configured
Without this option, such links are instead dropped, and transactions which
had updated such links will be replaced with an explanatory message.
- Serializes your entire database, creating a clone. This
option should be used if you want to migrate your RT database from one
database type to another (e.g. MySQL to Postgres). It is an error to
combine "--clone" with any option that limits object types
serialized. No dependency walking is performed when cloning.
"rt-importer" will detect that your serialized data set was
generated by a clone.
- Will generate an incremenal serialized dataset using the
data stored in your IncrementalRecords database table. This assumes that
you have created that table and run RT using the Record_Local.pm shim as
documented in "docs/incremental-export/".
- --gc n
- Adjust how often the garbage collection sweep is done;
lower numbers are more frequent. See "GARBAGE COLLECTION".
- --page n
- Adjust how many rows are pulled from the database in a
single query. Disable paging by setting this to 0. Defaults to 100.
Keep in mind that rows from RT's Attachments table are the limiting factor
when determining page size. You should likely be aiming for 60-75% of your
total memory on an otherwise unloaded box.
- Do not show graphical progress UI.
- Do not show graphical progress UI, but rather log was each
row is written out.
"rt-serializer" maintains a priority queue of objects to serialize, or
searches which may result in objects to serialize. When inserting into this
queue, it does no checking if the object in question is already in the queue,
or if the search will contain any results. These checks are done when the
object reaches the front of the queue, or during periodic garbage collection.
During periodic garbage collection, the entire queue is swept for objects which
have already been serialized, occur more than once in the queue, and searches
which contain no results in the database. This is done to reduce the memory
footprint of the serialization process, and is triggered when enough new
objects have been placed in the queue. This parameter is tunable via the
"--gc" parameter, which defaults to running garbage collection every
5,000 objects inserted into the queue; smaller numbers will result in more
frequent garbage collection.
The default of 5,000 is roughly tuned based on a database with several thousand
tickets, but optimal values will vary wildly depending on database
configuration and size. Values as low as 25 have provided speedups with
smaller databases; if speed is a factor, experimenting with different
"--gc" values may be helpful. Note that there are significant
boundary condition changes in serialization rate, as the queue empties and
fills, causing the time estimates to be rather imprecise near the start and
end of the process.
Setting "--gc" to 0 turns off all garbage collection. Be aware that
this will bloat the memory usage of the serializer. Any negative value for
"--gc" turns off periodic garbage collection and instead objects
already serialized or in the queue are checked for at the time they would be