Struct PoolOpts

pub struct PoolOpts { /* private fields */ }

Connection pool options.

let pool_opts = PoolOpts::default()
    .with_constraints(PoolConstraints::new(15, 30).unwrap())
    .with_reset_connection(false);

Implementations

impl PoolOpts

pub fn new() -> Self

Calls Self::default.

pub fn with_constraints(self, constraints: PoolConstraints) -> Self

Creates the default PoolOpts with the given constraints.

pub fn constraints(&self) -> PoolConstraints

Returns pool constraints.

pub fn with_reset_connection(self, reset_connection: bool) -> Self

Sets whether to reset the connection upon returning it to a pool (defaults to true).

Default behavior increases reliability but comes with cons:

• reset procedure removes all prepared statements, i.e. kills prepared statements cache
• connection reset is quite fast but requires additional client-server roundtrip (might require re-authentication for older servers)

The purpose of the reset procedure is to:

• rollback any opened transactions
• reset transaction isolation level
• reset session variables
• delete user variables
• remove temporary tables
• remove all PREPARE statement (this action kills prepared statements cache)

So to increase overall performance you can safely opt-out of the default behavior if you are not willing to change the session state in an unpleasant way.

It is also possible to selectively opt-in/out using crate::PooledConn::reset_connection.

Connection URL

You can use reset_connection URL parameter to set this value. E.g.

let opts = Opts::from_url("mysql://localhost/db?reset_connection=false")?;
assert_eq!(opts.get_pool_opts().reset_connection(), false);

pub fn reset_connection(&self) -> bool

Returns the reset_connection value (see PoolOpts::with_reset_connection).

pub fn with_check_health(self, check_health: bool) -> Self

Sets whether to check connection health upon retrieving it from a pool (defaults to true).

If true, then Conn::ping will be invoked on a non-fresh pooled connection.

Connection URL

Use check_health URL parameter to set this value. E.g.

let opts = Opts::from_url("mysql://localhost/db?check_health=false")?;
assert_eq!(opts.get_pool_opts().check_health(), false);

pub fn check_health(&self) -> bool

Trait Implementations

impl Clone for PoolOpts

fn clone(&self) -> PoolOpts

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PoolOpts

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

Formats the value using the given formatter.

impl Default for PoolOpts

fn default() -> Self

Returns the “default value” for a type.

impl Hash for PoolOpts

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for PoolOpts

fn eq(&self, other: &PoolOpts) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for PoolOpts

impl StructuralPartialEq for PoolOpts