What do common versioning terms mean?

Answer

Note:
This article pertains to ArcGIS versions 8.x and 9.x. Later versions of ArcGIS may contain different functionality, as well as different names and locations for menus, commands and geoprocessing tools.

The following article offers basic definitions for common versioning terms. For a more expansive list of versioning terms, refer to ArcMap: Versioning vocabulary or ArcGIS Pro: Versioning vocabulary.

What is a version

A version represents a snapshot in time of an entire geodatabase and contains all the datasets in said geodatabase.

Versions are not separate copies of the geodatabase. Instead, versions and the transactions that take place within them are tracked in system tables. This isolates a user's work across multiple edit sessions, allowing users to edit without locking features in the production version or immediately impacting other users and without having to make copies of the data.

What is a state?

A geodatabase state is a record of a change made to a version. Every time you edit a feature within a version, a new state is created.

What is a lineage?

A lineage (also known as a state tree) is a sequence of states, starting with the beginning state and ending with the current state. It represents a series of changes made to a geodatabase. Each branch in the tree or lineage records how a version has evolved.

What are delta tables?

The adds and deletes tables for a dataset are collectively referred to as the delta tables because they store changes (deltas) made to the dataset.

What is a reconcile?

The reconcile process compares the edit version and the target version to find conflicts between the two. Conflicts arise when your edits contradict edits made to the target version by another user.

You can set rules to define conflicts—whether conflicts are changes made to a row or any changes made in a column—and the default behavior for conflict resolution—whether the edit version or target version changes take precedence.

Reconciling only updates the edit version so that ArcGIS can check for conflicts; it does not merge changes into the target version. You must review and resolve any conflicts detected during the reconcile process before you can merge them with the target version through the post process.

What is a post?

The post process merges changes from your edit version to the target version.

The post operation can only complete if the target version has not been modified since the reconcile operation was completed. If the target version has been modified in the interim, reconcile again before posting.

What is a compress?

The compress operation is performed on versioned geodatabases. Its primary purpose is to remove unreferenced states and their associated delta table rows, and move entries in the delta tables common to all versions into the base tables. This reduces the amount of data the database needs to search through for each version query, thereby improving query performance and system response time.

Versioned geodatabases that are actively edited must be compressed frequently (daily or weekly, depending on edit volume). The more time passes between compress operations, the longer the compress operation will take to complete.