Search Time Limits
Unfortunately, the search time limitations are not simple to describe accurately since they are implementation limitations of various portions of the search engine, rather than a straightforward, uniformly-enforced limit on the physical number of nodes/links.
By way of background, the Verity search engine is built on the notion that topics represent search concepts. Queries that go beyond a single word or phrase typically involve the ACCRUE-class operators (ACCRUE, AND, OR) to combine several branches of evidence in a topic tree. At search time, the combined evidence is evaluated by a stack-based engine.
The stack engine imposes some restrictions for ACCRUE-class topics. Its limited stack space imposes the restriction of 1024 children for any single ACCRUE-class node and about 5,300 total notes (16000/3 to be precise), in a topic. These limits are detected gracefully while building the query (before running the search), and result in an error. The second limit can be worked around by having named sub-nodes in a large topic and building the topic set with this mktopics option:
- -indextype namedonly
The above option causes separate queries to be built for each named sub-topic, leaving more space for each query. Carrying this process to the extreme, however, will reduce the effectiveness of the topic index for the top-level topic.
Copyright © 2001, Verity, Inc. All rights
reserved.