67 lines
2.2 KiB
MySQL
67 lines
2.2 KiB
MySQL
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-- Fix Race Condition in Member ID Generation
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-- ============================================
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-- Problem: Current implementation uses MAX() or COUNT() which allows duplicate IDs
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-- if two registrations happen simultaneously.
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--
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-- Solution: Use PostgreSQL sequence for atomic ID generation.
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-- Step 1: Create sequence for member IDs
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-- Find the highest existing member number to set starting point
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DO $$
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DECLARE
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max_num INTEGER;
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BEGIN
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-- Extract numeric part from existing member_ids (handles both MUSA-XXXX and MUSA-YYYY-XXXX formats)
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SELECT COALESCE(
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MAX(
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CAST(
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SUBSTRING(
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member_id FROM '[0-9]+$' -- Get trailing digits
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) AS INTEGER
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)
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),
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0
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) INTO max_num
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FROM public.members;
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-- Create sequence starting from next available number
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EXECUTE format('CREATE SEQUENCE IF NOT EXISTS member_id_seq START WITH %s', max_num + 1);
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END $$;
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-- Step 2: Replace trigger function to use sequence
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CREATE OR REPLACE FUNCTION generate_member_id()
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RETURNS TRIGGER AS $$
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DECLARE
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next_num INTEGER;
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current_year TEXT;
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BEGIN
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-- Only generate if member_id is not already set
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IF NEW.member_id IS NOT NULL THEN
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RETURN NEW;
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END IF;
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-- Get next number from sequence (atomic operation)
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next_num := NEXTVAL('member_id_seq');
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current_year := EXTRACT(YEAR FROM CURRENT_DATE)::TEXT;
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-- Format: MUSA-YYYY-XXXX (matches application format)
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NEW.member_id := 'MUSA-' || current_year || '-' || LPAD(next_num::TEXT, 4, '0');
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RETURN NEW;
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END;
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$$ LANGUAGE plpgsql;
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-- Step 3: Ensure trigger exists (should already exist from 001_initial_schema.sql)
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DROP TRIGGER IF EXISTS set_member_id ON public.members;
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CREATE TRIGGER set_member_id
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BEFORE INSERT ON public.members
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FOR EACH ROW
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WHEN (NEW.member_id IS NULL)
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EXECUTE FUNCTION generate_member_id();
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-- Step 4: Add index on member_id for faster lookups (if not exists)
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CREATE INDEX IF NOT EXISTS idx_members_member_id ON public.members(member_id);
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COMMENT ON SEQUENCE member_id_seq IS 'Atomic sequence for generating unique member IDs. Used by generate_member_id() trigger.';
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COMMENT ON FUNCTION generate_member_id() IS 'Atomically generates member IDs using NEXTVAL(member_id_seq) to prevent race conditions.';
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