Crate poolsim_core 

poolsim-core

poolsim-core is the Rust library crate for connection-pool sizing.

It is the simulation and analysis engine behind the poolsim workspace.

Scope

The current release focuses on sizing calculation, not runtime pool enforcement.

It provides:

• workload and pool validation
• latency distribution fitting
• Erlang-C helpers
• Monte Carlo queue simulation
• pool-size optimization
• sensitivity analysis
• step-load analysis

Install

[dependencies]
poolsim-core = "0.1.0"

Primary APIs

Use the crate-root APIs for the most common workflows:

• simulate: full recommendation workflow
• evaluate: score a fixed pool size
• sweep: generate sensitivity rows with default options
• sweep_with_options: generate sensitivity rows with explicit options

Important public modules:

• poolsim_core::types
• poolsim_core::distribution
• poolsim_core::erlang
• poolsim_core::monte_carlo
• poolsim_core::optimizer
• poolsim_core::sensitivity
• poolsim_core::error

Example

use poolsim_core::{
    simulate,
    types::{PoolConfig, SimulationOptions, WorkloadConfig},
};

let workload = WorkloadConfig {
    requests_per_second: 220.0,
    latency_p50_ms: 8.0,
    latency_p95_ms: 32.0,
    latency_p99_ms: 85.0,
    raw_samples_ms: None,
    step_load_profile: None,
};

let pool = PoolConfig {
    max_server_connections: 120,
    connection_overhead_ms: 2.0,
    idle_timeout_ms: None,
    min_pool_size: 3,
    max_pool_size: 24,
};

let report = simulate(&workload, &pool, &SimulationOptions::default()).unwrap();
assert!(report.optimal_pool_size >= 3);

Output

The main simulation output includes:

• recommended pool size
• confidence interval
• cold-start minimum pool size
• utilisation ratio
• queue-wait metrics
• sensitivity rows
• optional step-load analysis
• warnings

See Also

• Workspace repository: https://github.com/gregorian-09/poolsim
• Detailed library guide: https://github.com/gregorian-09/poolsim/blob/main/docs/library-api.md
• Sizing calculator guide: https://github.com/gregorian-09/poolsim/blob/main/docs/sizing-calculator.md

Notes

• For CLI usage, see the poolsim-cli crate.
• For HTTP and WebSocket usage, see the poolsim-web crate.

Re-exports

pub use types::DistributionModel;

pub use types::QueueModel;

pub use types::RiskLevel;

Modules

distribution

Distribution fitting and sampling utilities. Distribution fitting and sampling for workload latency inputs.

erlang

Erlang-C queueing formulas. Erlang-C queueing helpers used by sizing and sensitivity calculations.

error

Error type and helpers. Error types and helpers for the public poolsim-core API.

monte_carlo

Monte Carlo queue simulation engine. Monte Carlo queue simulation primitives.

optimizer

Pool-size optimization routines. Pool-size optimization routines.

sensitivity

Sensitivity analysis routines. Sensitivity analysis across a configured pool-size range.

types

Public input/output data models. Public data models used by poolsim-core.

Constants

MIN_FULL_SIMULATION_ITERATIONS

Minimum iteration floor used by full simulation for stable estimates.

PERFORMANCE_CONTRACT_WARNING

Performance warning text emitted by benchmark/helpers when threshold is exceeded.

Functions

emit_performance_contract_warning

Emits the performance contract warning when elapsed time exceeds threshold.

evaluate

Evaluates a fixed pool size against the workload/options.

simulate

Runs full pool-size optimization and returns a simulation report.

sweep

Generates a sensitivity table using default simulation options.

sweep_with_options

Generates a sensitivity table using explicit simulation options.