Struct tidb_query_executors::BatchSlowHashAggregationExecutor

pub struct BatchSlowHashAggregationExecutor<Src: BatchExecutor>(AggregationExecutor<Src, SlowHashAggregationImpl>);

Slow Hash Aggregation Executor supports multiple groups but uses less efficient ways to store group keys in hash tables.

FIXME: It is not correct to just store the serialized data as the group key. See pingcap/tidb#10467.

Implementations

impl BatchSlowHashAggregationExecutor<Box<dyn BatchExecutor<StorageStats = ()>>>

pub fn check_supported(descriptor: &Aggregation) -> Result<()>

Checks whether this executor can be used.

impl<Src: BatchExecutor> BatchSlowHashAggregationExecutor<Src>

pub fn new(
    config: Arc<EvalConfig>,
    src: Src,
    group_by_exp_defs: Vec<Expr>,
    aggr_defs: Vec<Expr>
) -> Result<Self>

fn new_impl(
    config: Arc<EvalConfig>,
    src: Src,
    group_by_exps: Vec<RpnExpression>,
    aggr_defs: Vec<Expr>,
    aggr_def_parser: impl AggrDefinitionParser
) -> Result<Self>

Trait Implementations

impl<Src: BatchExecutor> BatchExecutor for BatchSlowHashAggregationExecutor<Src>

type StorageStats = Src::StorageStats

fn schema(&self) -> &[FieldType]

Gets the schema of the output.

fn next_batch(&mut self, scan_rows: usize) -> BatchExecuteResult

Pulls next several rows of data (stored by column).

fn collect_exec_stats(&mut self, dest: &mut ExecuteStats)

Collects execution statistics (including but not limited to metrics and execution summaries) accumulated during execution and prepares for next collection.

fn collect_storage_stats(&mut self, dest: &mut Self::StorageStats)

Collects underlying storage statistics accumulated during execution and prepares for next collection.

fn take_scanned_range(&mut self) -> IntervalRange

fn can_be_cached(&self) -> bool

fn collect_summary(
    self,
    output_index: usize
) -> WithSummaryCollector<ExecSummaryCollectorEnabled, Self> where
    Self: Sized,