PosgreSQL hybrid search #958
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Include: - Text search index - Hybrid Search configuration - Vector or hybrid search
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@microsoft-github-policy-service agree |
- Index name should be different per table. - Add missing filter
dluc
reviewed
Jan 8, 2025
| @@ -175,7 +183,8 @@ public async Task CreateTableAsync( | |||
| {this._colContent} TEXT DEFAULT '' NOT NULL, | |||
| {this._colPayload} JSONB DEFAULT '{{}}'::JSONB NOT NULL | |||
| ); | |||
| CREATE INDEX IF NOT EXISTS idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_content ON {tableName} USING GIN(to_tsvector('english',{this._colContent})); | |||
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For users already using KM + PG, their tables will lack this index. I'm assuming that if the index is missing, it will only affect performance, making hybrid search very slow, without causing any error.
dluc
reviewed
Jan 8, 2025
| @@ -175,7 +183,8 @@ public async Task CreateTableAsync( | |||
| {this._colContent} TEXT DEFAULT '' NOT NULL, | |||
| {this._colPayload} JSONB DEFAULT '{{}}'::JSONB NOT NULL | |||
| ); | |||
| CREATE INDEX IF NOT EXISTS idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_content ON {tableName} USING GIN(to_tsvector('english',{this._colContent})); | |||
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Should the language be configurable?
dluc
reviewed
Jan 8, 2025
| @@ -175,7 +183,8 @@ public async Task CreateTableAsync( | |||
| {this._colContent} TEXT DEFAULT '' NOT NULL, | |||
| {this._colPayload} JSONB DEFAULT '{{}}'::JSONB NOT NULL | |||
| ); | |||
| CREATE INDEX IF NOT EXISTS idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_tags ON {tableName} USING GIN({this._colTags}); | |||
| CREATE INDEX IF NOT EXISTS {tableName}_idx_content ON {tableName} USING GIN(to_tsvector('english',{this._colContent})); | |||
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could you update this file too https://github.com/microsoft/kernel-memory/blob/main/extensions/Postgres/README.md please?
dluc
reviewed
Jan 8, 2025
| @@ -413,6 +426,8 @@ DO UPDATE SET | |||
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| // Column names | |||
| string columns = withEmbeddings ? this._columnsListWithEmbeddings : this._columnsListNoEmbeddings; | |||
| string columnsHibrid = this._columnsListHybrid; | |||
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nit: var name typo columnsHibrid => columnsHybrid
dluc
reviewed
Jan 8, 2025
Comment on lines
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| string columnsHibrid = this._columnsListHybrid; | ||
| string columnsListHybridCoalesce = this._columnsListHybridCoalesce; |
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these 2 vars could be removed, is there a reason to copy the values?
dluc
reviewed
Jan 8, 2025
Comment on lines
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| FROM {tableName}, plainto_tsquery('english', @query) query | ||
| WHERE {filterSqlHybridText} AND to_tsvector('english', {this._colContent}) @@ query | ||
| ORDER BY ts_rank_cd(to_tsvector('english', {this._colContent}), query) DESC |
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ditto: language should be configurable
dluc
reviewed
Jan 8, 2025
Comment on lines
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| COALESCE(1.0 / (60 + semantic_search.rank), 0.0) + | ||
| COALESCE(1.0 / (60 + keyword_search.rank), 0.0) AS {colDistance} |
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could you document or point to documentation explaining these formulas? e.g. what is 60?
dluc
reviewed
Jan 8, 2025
| COALESCE(semantic_search.{this._colTags}, keyword_search.{this._colTags}) AS {this._colTags}, | ||
| COALESCE(semantic_search.{this._colContent}, keyword_search.{this._colContent}) AS {this._colContent}, | ||
| COALESCE(semantic_search.{this._colPayload}, keyword_search.{this._colPayload}) AS {this._colPayload}, | ||
| COALESCE(semantic_search.{this._colEmbedding}, keyword_search.{this._colEmbedding}) AS {this._colEmbedding}, |
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nit: remove the trailing comma (consistency with the way these values are used)
dluc
requested changes
Jan 8, 2025
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This PR Includes:
Motivation and Context (Why the change? What's the scenario?)
Vector search do not provide the best results in an important number of scenarios. Hybrid search provides better results.
High level description (Approach, Design)
This change includes a new parameter for activate hybrid search on PostgreSQL extension. This parameters defaults to the previous implementation (vector search).
The search will use vector search or hybrid search depending on the parameter.