Posts

PostgreSQL 10 identity columns explained

For PostgreSQL 10, I have worked on a feature called “identity columns”. Depesz already wrote a blog post about it and showed that it works pretty much like serial columns: CREATE TABLE test_old ( id serial PRIMARY KEY, payload text ); INSERT INTO test_old (payload) VALUES (‘a’), (‘b’), (‘c’) RETURNING *; and CREATE TABLE test_new […]

Performance of Sequences and Serials in Postgres-XL

In Postgres-XL, sequences are maintained at the Global Transaction Manager (GTM) to ensure that they are assigned non-conflicting values when they are incremented from multiple nodes. This adds significant overhead for a query doing thousands of INSERTs in a table with a serial column, incrementing sequence one at a time and making a network roundtrip […]