26 lines
1.3 KiB
MySQL
26 lines
1.3 KiB
MySQL
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-- Migration: Add covering indexes for task detail queries
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-- Date: 2026-01-25
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--
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-- This migration adds covering indexes to optimize queries by including
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-- all needed columns in the index, avoiding table lookups.
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--
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-- Covering indexes allow PostgreSQL to perform index-only scans,
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-- getting all data directly from the index without accessing the table.
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-- Covering index for subtasks query
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-- Includes all columns needed for subtasks selection to avoid table lookups
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CREATE INDEX IF NOT EXISTS idx_tasks_parent_deleted_covering
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ON tasks(parent_task_id, deleted, id)
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INCLUDE (name, completed, last_completed_at, reward_message, progression_base)
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WHERE deleted = FALSE;
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-- Covering index for wishlist name lookup
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-- Includes name and deleted flag for quick lookup without table access
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CREATE INDEX IF NOT EXISTS idx_wishlist_items_id_deleted_covering
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ON wishlist_items(id, deleted)
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INCLUDE (name)
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WHERE deleted = FALSE;
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COMMENT ON INDEX idx_tasks_parent_deleted_covering IS 'Covering index for subtasks query - includes all selected columns to avoid table lookups. Enables index-only scans for better performance.';
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COMMENT ON INDEX idx_wishlist_items_id_deleted_covering IS 'Covering index for wishlist name lookup - includes name to avoid table lookup. Enables index-only scans for better performance.';
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