On 11/20/2017 12:50 PM, Sundeep T wrote: > I initially asked this question regarding leading wildcards. This was a > typo, and what I meant was trailing wild card queries were slow. So queries > like text:'hello*" are slow. We were expecting since the string field is > already indexed, the searches should be fast, but that seems to be not the > case
The following is my understanding of wildcard queries: Let's say that the wildcard "hello*" matches one million terms on the text field you're searching. I have no idea what the actual number would be ... one million is arbitrary. Behind the scenes, that query object will quite literally have one million different terms in it, and ALL of those terms will be checked against the index to obtain the list of matching documents. Even if each check is pretty fast, doing a million of them to satisfy the query is going to take some time. Also, it's going to take some time to gather the one million matching terms in the first place. The term gathering step is particularly slow with leading wildcards, but even trailing wildcards can result in slow queries. Wildcards that only match a few terms might be quick, but predicting the number of matching terms BEFORE the query is executed is difficult. Thanks, Shawn
