Enum mz_adapter::session::TransactionStatus

pub enum TransactionStatus<T> {
    Default,
    Started(Transaction<T>),
    InTransaction(Transaction<T>),
    InTransactionImplicit(Transaction<T>),
    Failed(Transaction<T>),
}

The transaction status of a session.

PostgreSQL’s transaction states are in backend/access/transam/xact.c.

Variants

Default

Idle. Matches TBLOCK_DEFAULT.

Started(Transaction<T>)

Running a single-query transaction. Matches TBLOCK_STARTED. In PostgreSQL, when using the extended query protocol, this may be upgraded into multi-statement implicit query (see Self::InTransactionImplicit). Additionally, some statements may trigger an eager commit of the implicit transaction, see: https://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=f92944137. In Materialize however, we eagerly commit all statements outside of an explicit transaction when using the extended query protocol. Therefore, we can guarantee that this state will always be a single-query transaction and never be upgraded into a multi-statement implicit query.

InTransaction(Transaction<T>)

Currently in a transaction issued from a BEGIN. Matches TBLOCK_INPROGRESS.

InTransactionImplicit(Transaction<T>)

Currently in an implicit transaction started from a multi-statement query with more than 1 statements. Matches TBLOCK_IMPLICIT_INPROGRESS.

Failed(Transaction<T>)

In a failed transaction. Matches TBLOCK_ABORT.

Implementations

impl<T: TimestampManipulation> TransactionStatus<T>

pub fn into_ops_and_lock_guard( self, ) -> (Option<TransactionOps<T>>, Option<WriteLocks>)

Extracts the inner transaction ops and write lock guard if not failed.

pub fn inner(&self) -> Option<&Transaction<T>>

Exposes the inner transaction.

pub fn inner_mut(&mut self) -> Option<&mut Transaction<T>>

Exposes the inner transaction.

pub fn is_ddl(&self) -> bool

Whether the transaction’s ops are DDL.

pub fn is_implicit(&self) -> bool

Expresses whether or not the transaction was implicitly started. However, its negation does not imply explicitly started.

pub fn is_in_multi_statement_transaction(&self) -> bool

Whether the transaction may contain multiple statements.

pub fn in_immediate_multi_stmt_txn(&self, when: &QueryWhen) -> bool

Whether the transaction is in a multi-statement, immediate transaction.

pub fn try_grant_write_locks( &mut self, guards: WriteLocks, ) -> Result<(), &WriteLocks>

Grants the writes lock to the inner transaction, returning an error if the transaction has already been granted write locks.

Panics

If self is TransactionStatus::Default, which indicates that the transaction is idle, which is not appropriate to assign the coordinator’s write lock to.

pub fn write_locks(&self) -> Option<&WriteLocks>

Returns the currently held WriteLocks, if this transaction holds any.

pub fn timeline(&self) -> Option<Timeline>

The timeline of the transaction, if one exists.

pub fn cluster(&self) -> Option<ClusterId>

The cluster of the transaction, if one exists.

pub fn catalog_state(&self) -> Option<&CatalogState>

Snapshot of the catalog that reflects DDL operations run in this transaction.

pub fn contains_ops(&self) -> bool

Reports whether any operations have been executed as part of this transaction

pub fn add_ops( &mut self, add_ops: TransactionOps<T>, ) -> Result<(), AdapterError>

Adds operations to the current transaction. An error is produced if they cannot be merged (i.e., a timestamp-dependent read cannot be merged to an insert).

The DDL variant is an exception and does not merge operations, but instead overwrites the old ops with the new ops. This is correct because it is only used in conjunction with the Dry Run catalog op which returns an error containing all of the ops, and those ops are passed to this function which then overwrites.

Panics

If the operations are compatible but the operation metadata doesn’t match. Such as reads at different timestamps, reads on different timelines, reads on different clusters, etc. It’s up to the caller to make sure these are aligned.

Trait Implementations

impl<T: Debug> Debug for TransactionStatus<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for TransactionStatus<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> From<&TransactionStatus<T>> for TransactionCode

fn from(status: &TransactionStatus<T>) -> TransactionCode

Convert from the Session’s version