Struct Connection 

pub struct Connection { /* private fields */ }

Thread-safe database connection for FFI.

This is a wrapper around LaminarDB that provides:

• Explicit Send + Sync markers for FFI safety
• close() method returning Result for error handling
• Untyped Arrow API without Rust trait bounds

Example

use laminar_db::api::Connection;

let conn = Connection::open()?;
conn.execute("CREATE SOURCE trades (symbol VARCHAR, price DOUBLE)")?;

let result = conn.query("SELECT * FROM trades")?;
println!("Got {} rows", result.num_rows());

conn.close()?;

Implementations

impl Connection

pub fn open() -> Result<Self, ApiError>

Open an in-memory database with default settings.

Errors

Returns ApiError if database creation fails.

pub fn open_with_config(config: LaminarConfig) -> Result<Self, ApiError>

Open with custom configuration.

Errors

Returns ApiError if database creation fails.

pub fn execute(&self, sql: &str) -> Result<ExecuteResult, ApiError>

Execute a SQL statement (blocking wrapper around async).

Supports: CREATE SOURCE/SINK/STREAM, DROP, SELECT, INSERT INTO, SHOW, DESCRIBE, EXPLAIN, CREATE MATERIALIZED VIEW.

Errors

Returns ApiError if SQL parsing, planning, or execution fails.

Panics

Panics if the internal thread used for async execution panics.

pub fn query(&self, sql: &str) -> Result<QueryResult, ApiError>

Execute SQL and wait for all results (materialized).

Errors

Returns ApiError if execution fails or the result is not a query.

pub fn query_stream(&self, sql: &str) -> Result<QueryStream, ApiError>

Execute SQL with streaming results.

Errors

Returns ApiError if execution fails or the result is not a query.

pub fn writer(&self, source_name: &str) -> Result<Writer, ApiError>

Get a writer for inserting data into a source.

Errors

Returns ApiError if the source is not found.

pub fn insert( &self, source_name: &str, batch: RecordBatch, ) -> Result<u64, ApiError>

Insert a RecordBatch directly into a source.

Returns the number of rows inserted.

Errors

Returns ApiError if the source is not found or ingestion fails.

pub fn get_schema(&self, name: &str) -> Result<SchemaRef, ApiError>

Get schema for a source or stream.

Errors

Returns ApiError::table_not_found if the name is not found.

pub fn list_sources(&self) -> Vec<String>

List all source names.

pub fn list_streams(&self) -> Vec<String>

List all stream names.

pub fn list_sinks(&self) -> Vec<String>

List all sink names.

pub fn start(&self) -> Result<(), ApiError>

Start the streaming pipeline.

Errors

Returns ApiError if the pipeline cannot be started.

Panics

Panics if the internal thread used for async execution panics.

pub fn close(self) -> Result<(), ApiError>

Explicitly close the connection.

Unlike Drop, this returns errors and ensures cleanup completes.

Errors

Currently always succeeds.

pub fn is_closed(&self) -> bool

Check if the connection is closed.

pub fn checkpoint(&self) -> Result<u64, ApiError>

Trigger a checkpoint that persists to disk.

Returns the checkpoint ID on success. The pipeline must be started first via start().

Errors

Returns ApiError if checkpointing fails or is not enabled.

Panics

Panics if the internal thread used for async execution panics.

pub fn is_checkpoint_enabled(&self) -> bool

Check if checkpointing is enabled.

pub fn source_info(&self) -> Vec<SourceInfo>

List source info with schemas and watermark columns.

pub fn sink_info(&self) -> Vec<SinkInfo>

List sink info.

pub fn stream_info(&self) -> Vec<StreamInfo>

List stream info with SQL.

pub fn query_info(&self) -> Vec<QueryInfo>

List active/completed query info.

pub fn pipeline_topology(&self) -> PipelineTopology

Get the pipeline topology graph.

pub fn pipeline_state(&self) -> String

Get the pipeline state as a string (“Created”, “Running”, “Stopped”, etc.).

pub fn pipeline_watermark(&self) -> i64

Get the global pipeline watermark.

pub fn total_events_processed(&self) -> u64

Get total events processed across all sources.

pub fn source_count(&self) -> usize

Get the number of registered sources.

pub fn sink_count(&self) -> usize

Get the number of registered sinks.

pub fn active_query_count(&self) -> usize

Get the number of active queries.

pub fn metrics(&self) -> PipelineMetrics

Get pipeline-wide metrics snapshot.

pub fn source_metrics(&self, name: &str) -> Option<SourceMetrics>

Get metrics for a specific source.

pub fn all_source_metrics(&self) -> Vec<SourceMetrics>

Get metrics for all sources.

pub fn stream_metrics(&self, name: &str) -> Option<StreamMetrics>

Get metrics for a specific stream.

pub fn all_stream_metrics(&self) -> Vec<StreamMetrics>

Get metrics for all streams.

pub fn cancel_query(&self, query_id: u64) -> Result<(), ApiError>

Cancel a running query by ID.

Errors

Returns ApiError if the query is not found.

pub fn shutdown(&self) -> Result<(), ApiError>

Gracefully shut down the streaming pipeline.

Unlike close(), this waits for in-flight events to drain.

Errors

Returns ApiError if the shutdown fails.

Panics

Panics if the internal thread used for async execution panics.

pub fn subscribe( &self, stream_name: &str, ) -> Result<ArrowSubscription, ApiError>

Subscribe to a named stream, returning an ArrowSubscription.

The stream must already exist (created via CREATE STREAM ... AS SELECT ...). Returns a channel-based subscription that delivers RecordBatches as they are produced by the streaming pipeline.

Errors

Returns ApiError if the stream is not found.

Trait Implementations

impl Send for Connection

impl Sync for Connection