vercel/next.js · error

Single item size exceeds maxSize

Error message

Single item size exceeds maxSize

What it means

LRUCache.set computes the item size via calculateSize (defaulting to 1) and throws when a single item's size exceeds the cache's total maxSize, because such an entry could never fit; callers must raise maxSize or store a smaller value.

Source

Thrown at packages/next/src/server/lib/lru-cache.ts:137

  /**
   * Sets a key-value pair in the cache.
   * If the key exists, updates the value and moves to head.
   * If new, adds at head and evicts from tail if necessary.
   *
   * Time Complexity:
   * - O(1) for uniform item sizes
   * - O(k) where k is the number of items evicted (can be O(N) for variable sizes)
   */
  public set(key: string, value: T): boolean {
    const size = this.calculateSize?.(value, key) ?? 1
    if (size <= 0) {
      throw new Error(
        `LRUCache: calculateSize returned ${size}, but size must be > 0. ` +
          `Items with size 0 would never be evicted, causing unbounded cache growth.`
      )
    }
    if (size > this.maxSize) {
      console.warn('Single item size exceeds maxSize')
      return false
    }

    const existing = this.cache.get(key)
    if (existing) {
      // Update existing node: adjust size and move to head (most recent)
      existing.data = value
      this.totalSize = this.totalSize - existing.size + size
      existing.size = size
      this.moveToHead(existing)
    } else {
      // Add new node at head (most recent position)
      const newNode = new LRUNode(key, value, size)
      this.cache.set(key, newNode)
      this.addToHead(newNode)
      this.totalSize += size
    }

View on GitHub (pinned to 0eb3775416)

Solutions

1. Reduce the cached item size below the configured maxSize, or raise the LRU cache maxSize.

When it happens

Trigger: Thrown at packages/next/src/server/lib/lru-cache.ts:137 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@0eb3775416 (2026-08-19). Data as JSON: /api/errors/8eaf25a448e42638. Report an issue: GitHub.