Unexpected deadlock issues in PostgreSQL during bulk inserts with transactions
I need some guidance on This might be a silly question, but I'm working with a deadlock situation in PostgreSQL while performing bulk inserts within a transaction. The scenario involves inserting multiple rows into two related tables, `orders` and `order_items`, where `order_items` has a foreign key pointing to `orders`. I'm using the following code snippet for my bulk insert: ```sql BEGIN; INSERT INTO orders (customer_id, order_date) VALUES (1, '2023-10-01'), (2, '2023-10-01'); INSERT INTO order_items (order_id, product_id, quantity) VALUES (1, 101, 2), (1, 102, 1), (2, 103, 1); COMMIT; ``` I ran this within a loop for a series of orders, and I expected it to work smoothly. Instead, I keep getting the behavior message: ``` behavior: deadlock detected DETAIL: Process 12345 waits for ShareLock on relation 16384 of database 5432; blocked by process 67890. HINT: See server log for query details. ``` After reviewing my code and the logic behind it, I attempted to optimize the inserts by adding indexes on the `order_items` table, but that didn't help the deadlock scenario. I also made sure that the transaction isolation level is set to `READ COMMITTED`, which seems standard for such operations. To troubleshoot, I added logging to capture the deadlock information, but the logs aren't pointing to any specific queries that could be causing the scenario. Additionally, I tried breaking the inserts into smaller batches, but I still encounter deadlocks intermittently. Could there be a specific configuration or optimization I'm overlooking with PostgreSQL (version 14.2)? Are there best practices for performing bulk inserts that can prevent deadlocks in scenarios like this? Any insights would be greatly appreciated! My team is using Sql for this application.