Advanced Settings

Some techniques to optimize Helma's strategy for managing objects from a relational table.

_children.loadmode=aggressive

When this is set for _children or a virtual node, all child objects will be fetched in one query. The default way is to just fetch an index of children consisting of the object's keys, and then fetch the objects on demand, which allows the Hop to scale to large child collections where only few of the objects are actually accessed.

_children.cachemode=aggressive

By default, Hop refreshes a children index when any object with the prototype contained in the subnodes was modified since the last access. By setting this flag on _children or a virtual node, children will only be refreshed when an object is added to or removed from the child collection itself, or an object already contained in it is modified.

_children.maxsize=XX

When specifying children (either directly or within a virtual container) an optional maxsize property can be used to limit the number of objects contained. A setting of e.g. 100 would cause the collection to contain maximally 100 objects, regardless of how many (matching) rows the database table contains.

propname.readonly=true

Use the readonly flag to tell the Hop never to update this column in the database. Actually the column won't be updated if the property is not modified, but this is like an extra layer of security.

propname.private=true

The readonly flag tells Hop to update this column in the database only, but to prevent any collections containing or any other object referring to the very object with that property.

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Page last modified on 2007-09-25 20:53 by tobi