Felipe Cardoso
2055320058
- Add Alembic migration to enable pgvector PostgreSQL extension - Required for RAG knowledge base and embedding storage Implements #19 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
"""Enable pgvector extension
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Revision ID: 0003
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Revises: 0002
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Create Date: 2025-12-30
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This migration enables the pgvector extension for PostgreSQL, which provides
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vector similarity search capabilities required for the RAG (Retrieval-Augmented
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Generation) knowledge base system.
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Vector Dimension Reference (per ADR-008 and SPIKE-006):
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---------------------------------------------------------
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The dimension size depends on the embedding model used:
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| Model | Dimensions | Use Case |
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|----------------------------|------------|------------------------------|
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| text-embedding-3-small | 1536 | General docs, conversations |
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| text-embedding-3-large | 256-3072 | High accuracy (configurable) |
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| voyage-code-3 | 1024 | Code files (Python, JS, etc) |
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| voyage-3-large | 1024 | High quality general purpose |
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| nomic-embed-text (Ollama) | 768 | Local/fallback embedding |
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Recommended defaults for Syndarix:
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- Documentation/conversations: 1536 (text-embedding-3-small)
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- Code files: 1024 (voyage-code-3)
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Prerequisites:
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--------------
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This migration requires PostgreSQL with the pgvector extension installed.
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The Docker Compose configuration uses `pgvector/pgvector:pg17` which includes
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the extension pre-installed.
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References:
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-----------
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- ADR-008: Knowledge Base and RAG Architecture
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- SPIKE-006: Knowledge Base with pgvector for RAG System
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- https://github.com/pgvector/pgvector
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"""
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from collections.abc import Sequence
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from alembic import op
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# revision identifiers, used by Alembic.
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revision: str = "0003"
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down_revision: str | None = "0002"
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branch_labels: str | Sequence[str] | None = None
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depends_on: str | Sequence[str] | None = None
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def upgrade() -> None:
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"""Enable the pgvector extension.
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The CREATE EXTENSION IF NOT EXISTS statement is idempotent - it will
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succeed whether the extension already exists or not.
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"""
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op.execute("CREATE EXTENSION IF NOT EXISTS vector")
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def downgrade() -> None:
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"""Drop the pgvector extension.
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Note: This will fail if any tables with vector columns exist.
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Future migrations that create vector columns should be downgraded first.
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"""
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op.execute("DROP EXTENSION IF EXISTS vector")
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