Enum UpdateMetadata

pub enum UpdateMetadata {
    Downgrade,
    Upgrade,
    Rollback,
}

Variants

Downgrade

Downgrades the leader region.

Upgrade

Upgrades the candidate region.

Rollback

Rolls back the downgraded region.

Implementations

impl UpdateMetadata

pub async fn downgrade_leader_region(&self, ctx: &mut Context) -> Result<()>

Downgrades the leader region.

Abort(non-retry):

• TableRoute is not found.

Retry:

• Failed to update TableRouteValue.
• Failed to retrieve the metadata of table.

About the failure of updating the TableRouteValue:

• There may be another RegionMigrationProcedure that is executed concurrently for other region. It will only update other region info. Therefore, It’s safe to retry after failure.

• There is no other DDL procedure executed concurrently for the current table.

impl UpdateMetadata

pub async fn rollback_downgraded_region(&self, ctx: &mut Context) -> Result<()>

Rollbacks the downgraded leader region if the candidate region is unreachable.

Abort(non-retry):

• TableRoute is not found.

Retry:

• Failed to update TableRouteValue.
• Failed to retrieve the metadata of table.

impl UpdateMetadata

async fn build_upgrade_candidate_region_metadata( &self, ctx: &mut Context, ) -> Result<Vec<RegionRoute>>

Returns new Vec.

async fn check_metadata_updated(&self, ctx: &mut Context) -> Result<bool>

Returns true if region metadata has been updated.

pub async fn upgrade_candidate_region(&self, ctx: &mut Context) -> Result<()>

Upgrades the candidate region.

Abort(non-retry):

• TableRoute or RegionRoute is not found. Typically, it’s impossible, there is no other DDL procedure executed concurrently for the current table.

Retry:

• Failed to update TableRouteValue.
• Failed to retrieve the metadata of table.

Trait Implementations

impl Debug for UpdateMetadata

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for UpdateMetadata

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for UpdateMetadata

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl State for UpdateMetadata

fn next<'life0, 'life1, 'async_trait>( &'life0 mut self, ctx: &'life1 mut Context, ) -> Pin<Box<dyn Future<Output = Result<(Box<dyn State>, Status)>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Yields the next State and Status.

fn as_any(&self) -> &dyn Any

Returns as Any.

fn name(&self) -> &'static str