Performance depending on the number and order of filters? #370
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Is there any performance gain in the order of applying filters? Is there any negative or positive impact depending on the number of filters used? |
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Replies: 2 comments 1 reply
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There is no indexing so indeed the more filters you have the slower it gets as every record in a given store will be checked. The algorithm is dumb so indeed the order could have some impact (in a AND the first filter will be checked first). If you really want to optimize the filter, the faster will be to use a custom filter where you access the raw data of each record directly. A query with complex filtering with lots of data could be slow for each getSnapshots call, however onSnapshots will be smart enough to only check the filtering on modified records. |
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Thank you very much for the extremely quick response! Sorry to ask without analyzing first. I noticed that there were no indexes other than the store name + key. But I didn't stop to look in depth at how the filters work. But from your answer I understand that it goes through all the documents in a single Loop, and applies the conditions in the order of registration. I imagine that if it is an AND and the first condition is not met, it does not validate the others, correct? The doubt arose when I was combining a CUSTON filter with other filters. Whether it would be more advantageous to write other conditions within the custon or use the methods already available for pre-filtering. I don't think it will make a difference, at most I pay attention to the use of AND /OR and their order. |
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That's correct. And in the same way if the first condition of a OR is met it does not check the others too. |
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There is no indexing so indeed the more filters you have the slower it gets as every record in a given store will be checked. The algorithm is dumb so indeed the order could have some impact (in a AND the first filter will be checked first). If you really want to optimize the filter, the faster will be to use a custom filter where you access the raw data of each record directly.
A query with complex filtering with lots of data could be slow for each getSnapshots call, however onSnapshots will be smart enough to only check the filtering on modified records.