perf: cache hidden post set in Redis to prevent DB pool exhaustion - #370
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The hide_pids_by_ids function was querying hive_posts_status on every API request with 'WHERE list_type=1 AND post_id IN :ids'. Even though the table is small (13K rows, 832KB) and has proper indexes, under burst traffic this flooded the DB connection pool (size=30), causing cascading timeouts up to 427 seconds. Confirmed via production RDS debug API (2026-04-20): - hive_posts_status: 13,764 rows, indexes exist and healthy - DB version: 27 (all migrations applied) - Scalyr showed 0.0% idle during peak, 56 queries >100s (pool queuing) Fix: Cache the full hidden post ID set in Redis (60s TTL) and filter in Python. This turns every hide_pids_by_ids call into a Redis lookup + Python set intersection, eliminating the DB query entirely.
kuny0707
approved these changes
Jun 11, 2026
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The hide_pids_by_ids function was querying hive_posts_status on every API request with 'WHERE list_type=1 AND post_id IN :ids'. Even though the table is small (13K rows, 832KB) and has proper indexes, under burst traffic this flooded the DB connection pool (size=30), causing cascading timeouts up to 427 seconds.
Confirmed via production RDS debug API (2026-04-20):
Fix: Cache the full hidden post ID set in Redis (60s TTL) and filter in Python. This turns every hide_pids_by_ids call into a Redis lookup