Struct QueryEngine 

pub struct QueryEngine { /* private fields */ }

Query engine with caching and statistics

Implementations

impl QueryEngine

pub fn new( storage: Arc<StorageEngine>, schema: Arc<SchemaManager>, _memory: Arc<MemoryManager>, config: &Config, ) -> Result<Self>

Create a new query engine

pub async fn execute(&self, cql: &str) -> Result<QueryResult>

Execute a CQL query

pub async fn execute_streaming( &self, cql: &str, config: StreamingConfig, ) -> Result<QueryResultIterator>

Execute a CQL query with streaming results (Issue #280)

Returns a QueryResultIterator that yields rows incrementally via a bounded channel, enabling memory-efficient processing of large result sets.

Arguments

• cql - The CQL query string to execute (must be a SELECT statement)
• config - Streaming configuration (buffer size, chunk hints)

Errors

Returns an error if:

• Query is not a SELECT statement
• SQL syntax is invalid
• Query execution fails

Memory Budget

The streaming approach stays within the 128MB target by using bounded channels and processing rows incrementally rather than materializing all results.

pub async fn execute_with_params( &self, cql: &str, _params: &[Value], ) -> Result<QueryResult>

Execute a query with parameters

pub async fn prepare(&self, cql: &str) -> Result<Arc<PreparedQuery>>

Prepare a query for repeated execution

pub async fn execute_prepared( &self, prepared: &PreparedQuery, params: &[Value], ) -> Result<QueryResult>

Execute a prepared query

pub fn stats(&self) -> QueryStats

Get query statistics

pub fn clear_caches(&self)

Clear all caches

pub fn clear_prepared_cache(&self)

Clear prepared statement cache

pub fn clear_plan_cache(&self)

Clear query plan cache

pub fn cache_stats(&self) -> CacheStats

Get cache statistics

pub async fn explain(&self, cql: &str) -> Result<ExplainResult>

Optimize a query (return execution plan without executing)

pub async fn analyze(&self, cql: &str) -> Result<AnalyzeResult>

Analyze query performance

pub async fn has_schema_for_table(&self, table: &str) -> bool

Check if schema is available for a table

pub async fn schema_status(&self, table: &str) -> SchemaStatus

Get detailed schema status for debugging

Trait Implementations

impl Debug for QueryEngine

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

Formats the value using the given formatter.