Find here answers to frequently asked questions on yuuvis® Momentum. If you have further questions, you can ask them in our Q&A portal.

DMS Schemata

Is it possible to change the object type of an already existing object?

No, it is not. The object type has to be specified in the object creation request by the system:objectTypeId property and cannot be modified later on. However, the concept of secondary object types (SOTs) might satisfy your needs. Those object types cannot be used to instantiate any object, but to assign or remove additional properties at runtime. Thus, it is possible to specify a generic object type with only few properties during the object creation and assign a characterizing SOT by a metadata update at any time. In case you want to build a client application based on our developer libraries, such characterizing SOTs have to be defined as primary SOTs.

Search

Why are some objects displayed on the first and second result page?

The request for the second result page in yuuvis® Momentum internally requests a new search with the same query condition. From the new result list, the second page is calculated and provided to you. If, e.g., some objects matching the query condition are created after you retrieved the first and before you retrieved the second page, some objects from the first page might now appear later in the total result list. Thus, they reappear on the second result page.

Troubleshooting

Why is the database locked sometimes after a service startup?

During the startup of services with database access, Liquibase locks the data tables by writing a specific entry in the DATABASECHANGELOGLOCK table. If the startup is cancelled for any reason, this entry might remain. In this case the services with a database connection (e.g. AUDIT, REGISTRY and RENDITION-REPOSITORY services) fail to start and will repeatedly log warnings containing waiting for changelog lock.

Example log:

INFO [audit,,] 8 --- [ main] liquibase.lockservice : Waiting for changelog lock....

The database has to be unlocked as described in the Liquibase documentation.

What can I do if updating/deleting an object takes longer than its locking time?

The API Gateway, REGISTRY service or REPOSITORY lock the affected DMS objects during the processing time of the following requests:

• update of metadata or content
• moving content
• object creation with reference to a binary content file that is already stored in yuuvis® Momentum
• object deletion
• creation, update or deletion of tags.

Thus, multiple parallel manipulations on the same object or content are prevented. However, the locking time for each process is limited to 600 s in the default configuration. If some update or deletion processes exceed this time, you have the possibility to configure a higher value by specifying the lock.leasetime parameter for the above mentioned services.

Note: We strongly recommend to look for the origin of the slow processing instead of increasing the locking time. In most cases, your issues indicate a problem with your search index, your database or a binary storage (e.g., one of them might be almost full). Especially for productive systems, it is important to fix the actual problem.