Range queries is leading to memory growth

[dremekie]

Hi. This is a great library and well-documented. I have a question I hope you can help with and would definitely help others.

The following is a minimal example that demonstrates my issue. The code iterates through batches of 100 keys and removes them from the database. The memory usage grows steadily until all keys are removed. Once all keys are removed, memory usage remains the same. Memory is being retained and not being released. When I execute the code, there is a steady climb from <50M to >490M memory. Once all keys are removed (over 110,000), memory growth stops but memory usage remains the same at > 490M.

Is there anything you can see that I am doing wrong?

import { open } from 'lmdb';
const opts = { path: './testdb', compression: true };

const db = open(opts);
const wait = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
while (true) {
  await wait(50);

  // Collect keys
  let keys = [];
  const iter = db.getKeys({ limit: 100, snapshot: true });
  for (const key of iter) {
    keys.push(key);
  }

  // Remove keys
  keys.forEach((key) => {
    db.remove(key);
    console.log('Key:', key);
  });
  keys = undefined;
}

await db.close();

[dremekie]

Just to add, when I comment out db.remove(key); (which means it continually fetches the same 100 keys), there is zero memory growth.