Why does a larger connection pool hurt performance?

More connections increase lock contention and context-switching overhead. HikariCP's formula recommends pool = (CPU cores × 2) + disk spindles. A 4-core server with SSD needs only ~10 connections for optimal throughput.

How do I size PgBouncer pools?

PgBouncer multiplexes many application connections onto fewer server connections. Set max_client_conn to the total application threads and pool_size to the formula value. Transaction-mode pooling is most efficient.

Connection Pool Sizing Formula Calculator

Determine optimal database connection pool size using the formula pool = cores × 2 + effective_spindle_count (HikariCP guideline). Avoid over-pooling and the associated context-switching overhead.

Networking

Algorithms

Binary & Number

Systems

Dev Metrics

IP Subnet Calculator

IP Address

CIDR Prefix

Network

192.168.1.0

Broadcast

192.168.1.255

Subnet Mask

255.255.255.0

First Host

192.168.1.1

Last Host

192.168.1.254

Usable Hosts

254

Binary breakdown:

IP: 11000000.10101000.00000001.00000000

Mask: 11111111.11111111.11111111.00000000

Net: 11000000.10101000.00000001.00000000

How It Works

Determine optimal database connection pool size using the formula pool = cores × 2 + effective_spindle_count (HikariCP guideline). Avoid over-pooling and the associated context-switching overhead

Each component has a specific meaning:

Formula pool = cores × 2 + effective_spindle_count — The formula pool = cores × 2 + effective_spindle_count recorded for the patient or scenario being assessed.

Note: Interpret the connection pool sizing result against the clinical thresholds and context described above.

How to Use

Enter the formula pool = cores × 2 + effective_spindle_count for the patient or scenario you are assessing. Determine optimal database connection pool size using the formula pool = cores × 2 + effective_spindle_count (HikariCP guideline). Avoid over-pooling and the associated context-switching overhead. Use the connection pool sizing result to inform your clinical assessment.