PostgreSQL Scripts for Database Administration

How to Find Missing Indexes in PostgreSQL A missing index means PostgreSQL reads every row in a table to find what it needs. This is called a sequential scan. For small tables, that is fine. For large tables, it is slow and wastes CPU and I/O. PostgreSQL tracks sequential scans in the pg_stat_all_tables view. You can …

Detect PostgreSQL Transaction ID Wraparound Before It Causes Downtime PostgreSQL assigns a transaction ID (XID) to every write transaction. These IDs are 32-bit integers, which means they can only count up to about 2 billion. When the counter gets close to the limit, PostgreSQL must freeze old transaction IDs to …

Find PostgreSQL Tables That Need VACUUM FREEZE PostgreSQL uses transaction IDs (XIDs) to track which rows are visible to which transactions. Over time, these IDs age. When a table's oldest unfrozen XID gets too old, PostgreSQL triggers an aggressive autovacuum to freeze it. This is controlled by the …

How to Estimate Table Bloat in PostgreSQL When you update or delete rows in PostgreSQL, the old row versions are not removed immediately. They stay in the table as dead tuples until VACUUM cleans them up. Over time, if VACUUM does not keep up, these dead rows pile up and the table grows larger than it needs to be. This …

How to Find Index Bloat and Wasted Space in PostgreSQL Just like tables, PostgreSQL indexes can become bloated over time. When rows are updated or deleted, the old index entries are not removed immediately. They stay in the index as dead entries, wasting space and slowing down index scans. B-tree indexes are the most …

How to Monitor PostgreSQL Index Build Progress Building an index on a large table can take minutes or even hours. Without progress tracking, it is hard to know if the build is almost done or barely started. PostgreSQL 12 introduced the pg_stat_progress_create_index view to fix this. It shows real-time progress for any …

How to Monitor PostgreSQL HOT Updates and Fillfactor When PostgreSQL updates a row, it normally writes a new row version and creates a new index entry pointing to it. This is safe, but it adds overhead — especially on tables with many indexes. HOT updates (Heap Only Tuple) are a smarter path. When a HOT update happens, …

How to Find Idle in Transaction Sessions in PostgreSQL An idle-in-transaction session is a database connection that has started a transaction but is not currently running a query. It is just sitting there, holding the transaction open. This is different from a regular idle connection, which has no open transaction. …

Grant SELECT on All Tables in PostgreSQL This PostgreSQL script creates a read-only user and grants SELECT privileges on all existing tables in a schema, plus ensures the same access is automatically applied to any future tables created in that schema. Purpose and Overview Third-party ETL tools, reporting tools, and …

Kill Idle PostgreSQL Sessions with SQL These PostgreSQL scripts terminate idle sessions that have been inactive for more than 15 minutes. Two variants are provided: one that targets idle sessions across all databases on the server, and one scoped to only the currently connected database. Purpose and Overview Idle and …