Rules

Below the list of rules supported by the Postgres Language Server, divided by group. Here's a legend of the emojis:

• The icon ✅ indicates that the rule is part of the recommended rules.

Safety

Rules that detect potential safety issues in your code.

Rule name	Description	Properties
addSerialColumn	Adding a column with a SERIAL type or GENERATED ALWAYS AS ... STORED causes a full table rewrite.	✅
addingFieldWithDefault	Adding a column with a DEFAULT value may lead to a table rewrite while holding an ACCESS EXCLUSIVE lock.	✅
addingForeignKeyConstraint	Adding a foreign key constraint requires a table scan and a SHARE ROW EXCLUSIVE lock on both tables, which blocks writes.	✅
addingNotNullField	Setting a column NOT NULL blocks reads while the table is scanned.	✅
addingPrimaryKeyConstraint	Adding a primary key constraint results in locks and table rewrites.	✅
addingRequiredField	Adding a new column that is NOT NULL and has no default value to an existing table effectively makes it required.
banCharField	Using CHAR(n) or CHARACTER(n) types is discouraged.
banConcurrentIndexCreationInTransaction	Concurrent index creation is not allowed within a transaction.	✅
banDropColumn	Dropping a column may break existing clients.	✅
banDropDatabase	Dropping a database may break existing clients (and everything else, really).
banDropNotNull	Dropping a NOT NULL constraint may break existing clients.	✅
banDropTable	Dropping a table may break existing clients.	✅
banTruncateCascade	Using TRUNCATE's CASCADE option will truncate any tables that are also foreign-keyed to the specified tables.
changingColumnType	Changing a column type may break existing clients.
constraintMissingNotValid	Adding constraints without NOT VALID blocks all reads and writes.
creatingEnum	Creating enum types is not recommended for new applications.
disallowUniqueConstraint	Disallow adding a UNIQUE constraint without using an existing index.
lockTimeoutWarning	Taking a dangerous lock without setting a lock timeout can cause indefinite blocking.	✅
multipleAlterTable	Multiple ALTER TABLE statements on the same table should be combined into a single statement.	✅
preferBigInt	Prefer BIGINT over smaller integer types.
preferBigintOverInt	Prefer BIGINT over INT/INTEGER types.
preferBigintOverSmallint	Prefer BIGINT over SMALLINT types.
preferIdentity	Prefer using IDENTITY columns over serial columns.
preferJsonb	Prefer JSONB over JSON types.
preferRobustStmts	Prefer statements with guards for robustness in migrations.
preferTextField	Prefer using TEXT over VARCHAR(n) types.
preferTimestamptz	Prefer TIMESTAMPTZ over TIMESTAMP types.
renamingColumn	Renaming columns may break existing queries and application code.
renamingTable	Renaming tables may break existing queries and application code.
requireConcurrentIndexCreation	Creating indexes non-concurrently can lock the table for writes.
requireConcurrentIndexDeletion	Dropping indexes non-concurrently can lock the table for reads.
runningStatementWhileHoldingAccessExclusive	Running additional statements while holding an ACCESS EXCLUSIVE lock blocks all table access.	✅
transactionNesting	Detects problematic transaction nesting that could lead to unexpected behavior.