peter
3a5212cd8a
The first checkpoint of an item and the final flush beside it both read no state and both inserted; the loser failed on uq_plex_user_item. Two first saves each made a Watch later list. Both are created by an ON CONFLICT DO NOTHING insert and then read; a partial unique index holds one Watch later per user, and the migration folds an existing second list into the first. Plex keeps one per-item state map (rollup.item_state_map).
56 lines
1.9 KiB
Python
56 lines
1.9 KiB
Python
"""One Watch later list per user, held by the database
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Revision ID: 0112_one_watch_later
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Revises: 0111_audit_request_id
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Create Date: 2026-10-20
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Watch later was made on a user's first save by a read then an insert, so two first saves at once
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each made a list, and the reader then picked between them at random. A partial unique index holds
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"one per user" now. An instance that already has a second list keeps the oldest: the others' videos
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move into it (after its own, in their order; one it already holds is not added twice), then they go.
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"""
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import sqlalchemy as sa
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from alembic import op
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revision: str = "0112_one_watch_later"
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down_revision: str | None = "0111_audit_request_id"
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branch_labels: str | None = None
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depends_on: str | None = None
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_EXTRA = """
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SELECT p.id, k.keep_id
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FROM playlists p
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JOIN (
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SELECT user_id, min(id) AS keep_id FROM playlists WHERE kind = 'watch_later' GROUP BY user_id
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) k ON k.user_id = p.user_id
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WHERE p.kind = 'watch_later' AND p.id <> k.keep_id
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"""
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def upgrade() -> None:
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op.execute(
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f"""
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INSERT INTO playlist_items (playlist_id, video_id, position, added_at)
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SELECT e.keep_id, i.video_id,
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(SELECT coalesce(max(position), -1) FROM playlist_items WHERE playlist_id = e.keep_id)
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+ row_number() OVER (PARTITION BY e.keep_id ORDER BY i.playlist_id, i.position, i.id),
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i.added_at
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FROM playlist_items i
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JOIN ({_EXTRA}) e ON e.id = i.playlist_id
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ON CONFLICT ON CONSTRAINT uq_playlist_video DO NOTHING
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"""
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)
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op.execute(f"DELETE FROM playlists WHERE id IN (SELECT id FROM ({_EXTRA}) e)")
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op.create_index(
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"uq_playlist_watch_later",
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"playlists",
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["user_id"],
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unique=True,
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postgresql_where=sa.text("kind = 'watch_later'"),
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)
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def downgrade() -> None:
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op.drop_index("uq_playlist_watch_later", table_name="playlists")
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