Stale Share

Stale Share is a computational result produced from a mining job that has already become outdated. The result itself can be mathematically correct, but by the time it reaches the pool, the associated work is no longer relevant.

The most common situation occurs when a new block is found by the network. Once a new block appears, the previous job may no longer be valid for continued mining. The pool sends new work to miners, but some devices can continue processing the previous job for a short period or submit results with a delay.

Common Causes of Stale Shares

• high latency between the miner and pool server;
• unstable internet connectivity;
• delayed delivery of a new job;
• network or server overload;
• slow command processing by the hardware;
• software errors or delays.

How the Stale Rate Is Measured

A pool can display the number or percentage of stale shares relative to all submitted results. A small number of stale shares can occur even during normal operation because of delays in propagating new jobs.

A persistently high stale-share rate can indicate that a significant amount of computational work is being performed on jobs that are no longer current. The metric is therefore useful for diagnosing network infrastructure and miner configuration.

A Stale Share differs from an Invalid Share: a stale result can be mathematically correct but outdated, while an invalid share fails the correctness requirements of the result itself.