Module effects 

Classify SQL plans by database, session, and transaction effects.

Modules

read_only

SQL commands forbidden by read-only transactions and snapshot-setting rules.

transaction_blocks

Transaction commands that require an explicit SQL block.

Structs

QueryEffectContext

Compose SQL definitions with the effects of planner rewrites and the embedded graph language.

Traits

QueryEffectCatalog

Read-only definitions required to classify plan effects before execution.

Functions

command_payload_may_write_database

Detect database-writing expressions and query sources embedded in an otherwise legal temporary-table DML command.

is_transaction_control

query_may_mutate_engine

SELECT is not synonymous with read-only: UQA exposes a small set of state-changing scalar functions, and SQL/PLpgSQL routines invoked from a projection can contain commands. Classify those plans before choosing the transaction mode so memory execution takes a rollback snapshot and SQLite opens a write transaction. Cloning the plan is bounded by query size and avoids the database-sized deep copy paid by a full memory snapshot.

query_may_write_database

Classify only database writes forbidden by PostgreSQL read-only transactions. Session-local effects such as random() and setseed() still require statement rollback bookkeeping but remain legal in read-only mode.

query_requires_statement_transaction

Some read-only operations still need a statement transaction. In particular, a PL/pgSQL block with an EXCEPTION arm opens a subtransaction even when neither branch writes data.