feat: Write/retrieve chunks using postgres #17
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This removes the dependency on Redis, and makes the chunks/embeddings in the postgres database work. There are some issues to be addressed, specifically deduplicating cases where multiple embeddings of the same chunk are retrieved. I plan to work on those in a follow-up PR, so that we can get the bulk of this in first.
dewy/common/collection_embeddings.py
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| FROM relevant_embeddings | ||
| JOIN chunk | ||
| ON chunk.id = relevant_embeddings.chunk_id | ||
| LIMIT $2 |
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It seems like we could invert this and use SELECT DISTINCT ... from chunk to get the deduplicated chunks.
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Maybe? I want to get something in first and then play with it. I'd like to be able to point a pgsql repl at the database with chunks loaded in, and then see what works (and also use explain to see what the query does, etc.). Deferring.
| url, extract_tables=self.extract_tables, extract_images=self.extract_images | ||
| ) | ||
| if extracted.is_empty(): | ||
| logger.error( |
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If this is an error, shouldn't it throw an exception?
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It could -- but with background tasks, there isn't really anything to do with that error. What I think we actually need to do is mark the document (or ingestion associated with the document) as failed and/or do some kind of dead letter. That said -- perhaps we shouldn't treat this as an error?
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| # Then, embed each of those chunks. | ||
| # We assume no chunks for the document existed before, so we can iterate | ||
| # over the chunks. |
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Can we not return the chunk ID's or something? This seems like an assumption that's going to cause bugs as soon as we support updating a document.
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We could. My thinking was that we could write them into the DB rather than trying to keep them in memory and then read them back out. But, I think that both llamaindex and various other embeddings will lead to the whole text having to fit in memory anyway during an ingest, so maybe it doesn't matter.
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Actually, I take that back. There isn't a great way to do that. Specifically:
- This uses executemany, which doesn't return anything.
- If we use
fetch, we can't provide a list of rows to insert -- it needs to be a single query.
I think I'll leave as is for this PR. I think we could handle update in a variety of ways:
- Introduce a new document ID and delete the old one.
- Add a "version" to each chunk, and query for only the chunks related to the current version.
- etc.
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yeah, including an "ingest version" or something that we could filter on the other side would work.
This removes the dependency on Redis, and makes the chunks/embeddings in the postgres database work.
There are some issues to be addressed, specifically deduplicating cases where multiple embeddings of the same chunk are retrieved. I plan to work on those in a follow-up PR, so that we can get the bulk of this in first.