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Synopsis

ampd --config <path> server [OPTIONS]

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Description

Starts one or more query servers for serving blockchain data through different protocols. By default, both query servers (Arrow Flight and JSON Lines) are started. Servers can be selectively enabled using flags. Default behavior: If no server flags (--flight-server, --jsonl-server) are specified, BOTH servers are enabled by default. When any server flag is specified, only the explicitly enabled servers will start. The server runs continuously until terminated (Ctrl+C or kill signal).

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Options

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--flight-server
boolean
default:"false"
Enable Arrow Flight RPC Server. This provides a high-performance binary protocol for querying data (default port 1602). Uses Apache Arrow Flight for efficient data transfer.Can also be set via the FLIGHT_SERVER environment variable.
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--jsonl-server
boolean
default:"false"
Enable JSON Lines Server. This provides a simple HTTP interface for querying data (default port 1603). Accepts SQL queries via POST requests and returns results in JSON Lines format.Can also be set via the JSONL_SERVER environment variable.

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Configuration

Server ports and query settings are configured in the TOML config file: 
# Server addresses
flight_addr = "0.0.0.0:1602"
jsonl_addr = "0.0.0.0:1603"

# Streaming settings
server_microbatch_max_interval = 100
keep_alive_interval = 60

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Configuration Fields

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flight_addr
string
default:"0.0.0.0:1602"
Arrow Flight server binding address and port
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jsonl_addr
string
default:"0.0.0.0:1603"
JSON Lines server binding address and port
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server_microbatch_max_interval
integer
Maximum blocks per streaming microbatch
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keep_alive_interval
integer
Seconds between keep-alive messages (minimum 30 seconds)

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Environment Overrides

export AMP_CONFIG_FLIGHT_ADDR="0.0.0.0:1602"
export AMP_CONFIG_JSONL_ADDR="0.0.0.0:1603"
export AMP_CONFIG_SERVER_MICROBATCH_MAX_INTERVAL="100"
export AMP_CONFIG_KEEP_ALIVE_INTERVAL="60"

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Available Endpoints

EndpointDefault PortProtocolStreamingUse Case
Arrow Flight1602gRPCYesHigh-performance queries, batch and streaming
JSON Lines1603HTTPNoSimple HTTP queries, batch only

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Examples

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Start Both Servers (Default)

ampd --config config.toml server
Starts both Arrow Flight (1602) and JSON Lines (1603) servers.

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Start Only Arrow Flight Server

ampd --config config.toml server --flight-server
Starts only the Arrow Flight RPC Server on port 1602.

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Start Only JSON Lines Server

ampd --config config.toml server --jsonl-server
Starts only the JSON Lines Server on port 1603.

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Using Environment Variables

export AMP_CONFIG=config.toml
export FLIGHT_SERVER=true
ampd server

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Verifying Server Status

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Check JSON Lines Endpoint

curl http://localhost:1603/health

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Check Arrow Flight Endpoint

# Requires grpcurl
grpcurl -plaintext localhost:1602 list

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Querying Examples

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JSON Lines Query

curl -X POST http://localhost:1603/query/jsonl \
  -H "Content-Type: application/json" \
  -d '{"sql": "SELECT 1 as value"}'

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Arrow Flight Query

See the Arrow Flight transport documentation for detailed client usage.

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Directory Configuration

ampd server requires --config (or AMP_CONFIG) to be provided. Default data, providers, and manifests directory paths are resolved relative to the config file’s parent directory only when the config file does not specify those paths. When the config file specifies data_dir, providers_dir, or manifests_dir, those values are used directly. This command does not create directories itself; it relies on the configured paths and any downstream components to create or validate storage locations as needed.

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Exit Codes

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0
success
Server shut down gracefully
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1
error
Error occurred during server operation or configuration is invalid

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See Also

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