Fail to Use index query when add order by desc about pgvector HOT 6 CLOSED

Yes, as specified in the README you need to use an ASC order sort (i.e use 1 - dist)

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The reason for this is that the approximate nearest neighbor (ANN) indexes provided by pgvector are designed to find nearest neighbors, which is an ascending sort. A descending sort would find a query vector's furthest neighbors, which would require a different indexing scheme.

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Yes, as specified in the README you need to use an ASC order sort (i.e use 1 - dist)

thanks for quick reply! I have try 1 - dist while still not use index, Is it because the indexed column underwent mathematical operations？

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Hi @GreateFang, yes, see the troubleshooting docs.

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Added a note about ascending order to that section as well in the commit above.

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got it ！thanks~

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