55 lines
1.8 KiB
Python
55 lines
1.8 KiB
Python
"""provenance-race: dedupe + UNIQUE(image_record_id, post_id) on image_provenance
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Revision ID: 0021
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Revises: 0020
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Create Date: 2026-05-26
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Closes the race in Importer._apply_sidecar's existence-check + INSERT pattern.
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Two workers writing for the same (image, post) pair both saw no existing row
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and both inserted, leaving duplicates that then broke .scalar_one_or_none()
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on every subsequent deep-scan rederive against those images
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(MultipleResultsFound). Most plausibly seeded when the 5-min recovery sweep
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re-enqueued a still-running long-import task and the second worker collided
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with the first inside _apply_sidecar.
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Migration steps:
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1. DELETE all but min(id) per (image_record_id, post_id) pair. Operator's
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DB had 2 affected pairs at write-time; harmless no-op if zero.
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2. Add UNIQUE constraint so the importer's new savepoint+IntegrityError
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recovery path can trip on collision and re-select, mirroring
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uq_source_artist_platform_url and uq_post_source_external_id.
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"""
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from typing import Sequence, Union
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from alembic import op
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revision: str = "0021"
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down_revision: Union[str, None] = "0020"
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branch_labels: Union[str, Sequence[str], None] = None
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depends_on: Union[str, Sequence[str], None] = None
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def upgrade() -> None:
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op.execute(
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"""
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DELETE FROM image_provenance ip1
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USING image_provenance ip2
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WHERE ip1.image_record_id = ip2.image_record_id
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AND ip1.post_id = ip2.post_id
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AND ip1.id > ip2.id
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"""
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)
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op.create_unique_constraint(
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"uq_image_provenance_image_post",
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"image_provenance",
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["image_record_id", "post_id"],
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)
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def downgrade() -> None:
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op.drop_constraint(
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"uq_image_provenance_image_post",
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"image_provenance",
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type_="unique",
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)
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