Forum Discussion
Cross Workspace Analytic Rule Performance
first, search should not be more performant than union, so the difference may be elsewhere.
As to your question: I can't think of a way to avoid repeating the query, however, I can make it simpler:
let Filter = (T:(EventID:int))
{
T | where EventID == 4624
};
union (workspace("a").SecurityEvent | invoke Filter()),(workspace("b").SecurityEvent | invoke Filter())While for a single condition it might not be much shorter, it is still more elegant, and will become much shorter if you have more conditions.
Microsoft
"search in" vs. "union": if you search in a small subset of tables and do "union *", then you might be faster. In general, search (and search in) is much slower: it usually implies "contains" across all fields which is the most expensive query. With union you can use any operator and more directly limit to fields.
Well, you can do search in (SecurityAlert, SecurityEvent) _ResourceId:"127.0.0.1", but then it would be exactly like a simlar union.
As to my example: do whatever you like in the function. Just remember to declare any field from the source table you will reference.
