Daily - February 8, 2023

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February 8, 2023

GitHub - cybertec-postgresql/pgfaceting: Faceted query acceleration for PostgreSQL using roaring bitmaps

RoaringBitmap PostgreSQL Extension facet

PostgreSQL unique constraint, but NULL conflicts with everything

PostgreSQL constraint Exclusion_constraint GiST

A foreign key pathology to avoid

PostgreSQL MVCC multixact lock

OK, sometimes you can lock tables.

DO $$
   BEGIN
   FOR i IN 1 .. 1000 LOOP
      BEGIN
         LOCK TABLE t NOWAIT;
         ALTER TABLE t ADD COLUMN i BIGINT;
         RETURN;
      EXCEPTION WHEN lock_not_available THEN
         PERFORM pg_sleep(1);
         CONTINUE;
      END;
   END LOOP;
   RAISE lock_not_available;
   END;
$$;

PostgreSQL lock MVCC