yagpcc

yagpcc (Yet Another Greenplum Command Center) is a diagnostic and monitoring agent for Greenplum clusters. It collects query and session telemetry from the database (via the yagp-hooks-collector extension), aggregates it across Master and Segment hosts, and exposes it over gRPC for real-time and historical use.

Features

• Collects query and session telemetry from the database (via the yagp-hooks-collector extension).
• Aggregates it across Master and Segment hosts.
• Exposes it over gRPC for real-time and historical use.
• Provides an HTTP CSV export API mirroring the gRPC GetGPInfo service for easy scripting and spreadsheet integration.

Documentation

Document	Description
Service architecture	Services, roles, interfaces (UDS, TCP, libpq, HTTP), data flow, and default listen ports.
Architecture overview	High-level design and system diagram (with Mermaid).
API description	gRPC API reference (GetGPInfo, ActionService), CSV HTTP API, messages, and metrics.
Per-process resource statistics	Procfs (GetPidProcStat) data flow per running query and proposed master-only 5/15/30-minute top-style averages (per-session and cluster-wide rollup).
Performance tuning	Memory limits (GOMEMLIMIT), config knobs (procfs, segment pull, stored queries, aggregation), Prometheus metrics reference, and pprof profiling guide.

Building

Prerequisites:

• Go 1.25+ (see go.mod).
• protoc compiler (see https://protobuf.dev/installation/ apt install -y protobuf-compiler)
• protoc-gen-go, use https://protobuf.dev/reference/go/go-generated/ go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
• protoc-gen-go-grpc, use go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@latest

Build the binary (generates protos and outputs to devbin/yagpcc):

make build

Or build without regenerating protos:

go build -o devbin/yagpcc ./cmd/server

The binary is produced at devbin/yagpcc.

Configuration

The application reads yagpcc.yaml from the current working directory. A valid config file is required to run.

Config files differ by role:

• Master — runs on the Greenplum master host: connects to the cluster, pulls data from segments, and exposes the aggregated gRPC API. Requires role: master and master_connection (and typically segment_pull_rate_sec, segment_pull_threads).
• Segment — runs on each segment host: collects local metrics and serves them to the master. Requires role: segment and listen_port.

Example configs are in cmd/server/:

File	Role	Use as
cmd/server/yagpcc_master.yaml	master	Template for master node: set master_connection.addrs, master_connection.password, and optionally sslrootcert.
cmd/server/yagpcc_segment.yaml	segment	Template for segment nodes.

Copy or adapt the right file to yagpcc.yaml in the directory from which you will run the binary (see Running).

Minimal structure:

Master (yagpcc.yaml):

role: master
listen_port: 1432
segment_pull_rate_sec: 3
segment_pull_threads: 2
master_connection:
  addrs:
    - host1:6432
    - host2:6432
  sslmode: allow
  password: "your_password"
app:
  logging:
    level: debug

Segment (yagpcc.yaml):

role: segment
listen_port: 1432
app:
  logging:
    level: debug

Adjust listen_port, logging, and other options as needed (see internal/config/config.go for full options).

Running

1. Use a config file for the correct role (master or segment) and save it as yagpcc.yaml in the directory where you will run the binary.
2. From that directory, run:

./devbin/yagpcc

The binary expects yagpcc.yaml in the current working directory; it does not take a config path argument.