Hi Dave,
I have three suggestions for you to try. The Channel.Maximum property happens to be automatically "optimized" for any DataFinder instance. You can notice which properties are optimized in DIAdem by seeing if there is a [...] button to the far right of any query condition you create that uses that property. If you see the [...] button, then that is an optimized property. In addition to the query condition value assistance that the [...] offers, optimizing a property is designed to accelerate the performance of queries that use that property in a query condition. So that might be why the Channel.Maximum condition query finishes faster.
Another suggestion is to try to search for Files when using your other query condition(s). Searching for Groups or Channels always takes longer than searching for Files. These 3 levels (File, Group, Channel) are stored in different SQL tables inside the DataFinder index, and the File table is always the smallest of the three, thus the faster querying. If you can get the File query to return, then try immediately afterwards to query the Group level. In the normal (row-based) query mode, previous results are cached in RAM, and searching for Groups in the Files you just queried will return faster than querying the Groups straightaway (without querying their parent Files first). If that works, then try to query the Channels immediately after querying their Groups.
The third suggestion is to switch from the standard row-based query mode to the column-based query mode. There are 2 icons at the top of the NAVIGATOR panel that show a highlighted row and column, respectively, within a grid of rows and columns. Once you switch to the column-based query mode, you have to specify BEFORE you run the query which property columns you want to return. Since the column-based query only returns the property columns you ask for, and not all the property columns (and parent/grandparent properties), it will return the query results much faster. As a side benefit, you can return more than the 32,000 maximum search results that the row-based query mode is limited to.
Can you describe what query you're using when NOT querying based on Channel.Maximum? Is it just one condition? If so, what are the components of the condition (Level, Name, Operator, Value)? If it's more than 1 condition, how many, and what's in them? You may not be comparing apples to apples with the queries you're using.
Brad Turpin
Senior Technical Support Engineer
National Instruments
