2.9 Merge Process
A merge process combines data from several source full-text index components into one target full-text index component. There are two types of merge processes: shadow merge process and master merge process.
The result of a shadow merge process is a shadow index component. The result of a master merge process is a new master index component and its corresponding AVDL backup file.
If a master merge process is in progress and there is a master index component in the catalog, it MUST be one of the source full-text index components for the master merge. If a master index component participates in a merge process, it MUST be a master merge process.