Struct BorrowedReader 

pub struct BorrowedReader<'a> { /* private fields */ }

A query Reader borrowed from a QuestDb pool.

Egress companion to BorrowedSender. Derefs to Reader, so the usual prepare / execute cursor flow works unchanged. On Drop the reader is returned to the reader pool, unless its transport has been torn down (or Self::drop_on_return was called), in which case it is dropped and the next borrow opens a fresh one.

BorrowedReader is not Send or Sync: the borrowed connection belongs to the borrowing thread for the duration of the borrow.

Implementations

impl<'a> BorrowedReader<'a>

pub fn drop_on_return(&mut self)

Force this borrowed reader to be dropped (not recycled) when the borrow ends.

Use normal Drop for healthy readers: the return path already retires readers whose transport was torn down, or whose pool has been closed. Call this after abandoning work or handling an error where the next borrower must not inherit this connection.

Methods from Deref<Target = Reader>

pub fn current_addr(&self) -> &Endpoint

The endpoint this connection is currently bound to. Borrowed from the configured address list, so the borrow lives as long as &self. Stable across connect-string reorderings, unlike the (deliberately not exposed) underlying address-list index.

pub fn bytes_received(&self) -> u64

Total wire bytes (frame header + payload) read off the transport since this connection was opened. Useful for benchmarking the effective throughput a query produces.

pub fn transport_torn_down(&self) -> bool

true when the underlying transport has been torn down (mid-stream cursor abandonment, fatal socket error, role-mismatch failover that couldn’t find a replacement). Pool return paths should treat such a reader as must-close.

pub fn credit_granted_total(&self) -> u64

Total bytes granted to the server via CREDIT (0x15) frames since this connection was opened. Useful for verifying that flow-control replenishment behaves as expected — in particular, that Cursor::cancel() doesn’t continue topping up the server’s budget while draining frames it’s about to discard.

pub fn read_ns(&self) -> u64

Diagnostic accumulator (nanoseconds): time spent in transport.read_frame(). Saturates at u64::MAX (~584 years). Reset to zero by Reader::reset_timing.

pub fn decode_ns(&self) -> u64

Diagnostic accumulator (nanoseconds): time spent in decode_frame(). Saturates at u64::MAX. Reset to zero by Reader::reset_timing.

pub fn reset_timing(&self)

Reset both read_ns and decode_ns accumulators to zero.

pub fn stats(&self) -> &Arc<ReaderStats>

Borrow the shared diagnostic counters. The FFI clones this at qwp_reader_from_conf time so its stat getters can read the counters without touching the UnsafeCell<Reader> that holds this Reader — eliminating the aliasing question of “what happens when a stat getter synthesises a &Reader while a laundered &mut Reader is in flight.”

pub fn server_info(&self) -> Option<&ServerInfo>

SERVER_INFO (0x18) captured at connect time. None only while a reconnect is in flight; the single QWP version always supplies it.

pub fn server_version(&self) -> Result<u8>

Negotiated QWP version this connection is using. Returns SocketError when the Reader is poisoned after a failed mid-query failover.

pub fn symbol_dict(&self) -> &SymbolDict

Connection-scoped symbol dictionary.

pub fn prepare<S: Into<String>>(&mut self, sql: S) -> ReaderQuery<'_>

Begin building a parametrised query. The returned ReaderQuery exclusively borrows the reader; only one in-flight cursor at a time. Append binds in placeholder order, then call .execute().

pub fn execute<S: Into<String>>(&mut self, sql: S) -> Result<Cursor<'_>>

Execute a SQL statement with no binds and return a streaming cursor. Convenience for self.prepare(sql).execute().

Trait Implementations

impl Debug for BorrowedReader<'_>

Available on crate feature _egress only.

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

Formats the value using the given formatter.

impl Deref for BorrowedReader<'_>

Available on crate feature _egress only.

type Target = Reader

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for BorrowedReader<'_>

Available on crate feature _egress only.

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl Drop for BorrowedReader<'_>

Available on crate feature _egress only.

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.