LISTEN/NOTIFY provides real-time pub-sub messaging. Publishers send notifications via NOTIFY. Subscribers receive notifications via LISTEN. I use it for cache invalidation, real-time updates, inter-process communication. Payloads up to 8000 bytes carr

Data archival moves old data to cheaper storage. I use partitioning for time-based archival. Detach old partitions, export to S3, drop table. Archive tables store historical data with reduced indexes. Understanding retention policies prevents runaway

Observability provides insight into database health and performance. I monitor key metrics—queries per second, connection count, cache hit ratio. Slow query logs identify performance problems. Query latency percentiles show user experience. Lock wait

Multi-tenancy serves multiple customers from one application. I implement tenant isolation via schemas, databases, or row-level security. Shared schema with tenant_id column is simplest—good indexing essential. Separate schemas per tenant improves iso

LATERAL joins enable correlated subqueries in FROM clause. Each row can reference previous table columns. I use LATERAL for top-N-per-group queries. CROSS JOIN LATERAL iterates for each row. LEFT JOIN LATERAL includes rows without matches. Understandi

Recursive CTEs traverse hierarchical data—org charts, category trees, graphs. I use WITH RECURSIVE for self-referential queries. Base case provides starting rows. Recursive case joins to previous iteration. Understanding termination prevents infinite

JSON and JSONB store semi-structured data. JSONB is binary format—faster, indexable. I use JSONB for flexible schemas, API responses, configuration. JSON operators extract values, filter documents. GIN indexes enable fast JSONB queries. Containment op

Query optimization maximizes performance through efficient execution plans. I analyze queries with EXPLAIN ANALYZE. Understanding sequential scans vs index scans guides optimization. Join order affects performance dramatically. Subquery optimization v

VACUUM reclaims storage from dead tuples. Updates and deletes leave dead rows—VACUUM removes them. Autovacuum runs automatically but needs tuning. VACUUM FULL rewrites entire table—requires lock, reclaims most space. Understanding bloat prevents perfo

Data import/export moves data between systems. I use COPY for bulk operations—orders of magnitude faster than INSERT. CSV format balances simplicity and performance. Binary format is faster but less portable. Streaming import handles large files witho

Geospatial data represents geographic locations and shapes. I use PostGIS for spatial queries. Point data stores coordinates—latitude, longitude. LineString represents paths. Polygon defines areas. Spatial indexes (GIST) enable fast proximity queries.

Time-series data tracks measurements over time—metrics, logs, sensor data. I use TimescaleDB for time-series workloads. Hypertables automatically partition by time. Continuous aggregates precompute rollups. Time-based retention policies auto-delete ol