test: cover Excache.EvictionRuntimeTest and configure

test/excache/eviction_runtime_test.exs

@@ -0,0 +1,202 @@
+defmodule Excache.EvictionRuntimeTest do
+  use Excache.Test.ServerCase, async: false
+
+  alias Excache.Aof
+  alias Excache.Config
+  alias Excache.Eviction.Runner
+  alias Excache.Eviction.Tracker
+  alias Excache.Store
+
+  @payload String.duplicate("x", 1000)
+  @oom {:error, "OOM command not allowed when used memory > 'maxmemory'"}
+
+  setup_all do
+    Application.put_env(:excache, :eviction_interval, 60_000)
+    Process.sleep(250)
+
+    on_exit(fn -> Application.delete_env(:excache, :eviction_interval) end)
+    :ok
+  end
+
+  setup do
+    Application.put_env(:excache, :eviction_recheck, 0)
+    Config.reset()
+    Tracker.clear(Tracker)
+    Runner.resetStats()
+
+    on_exit(fn ->
+      Config.reset()
+      Application.delete_env(:excache, :eviction_recheck)
+    end)
+
+    :ok
+  end
+
+  test "allkeys-lru drops the coldest keys when a write crosses maxmemory", %{conn: conn} do
+    conn = configure(conn, ["maxmemory-policy", "allkeys-lru", "maxmemory-samples", "64"])
+    conn = fill(conn, 1..40)
+
+    {before, conn} = stats(conn)
+    assert before["keys.count"] == 40
+    assert before["total.allocated"] > 40_000
+
+    Process.sleep(5)
+    conn = touch(conn, 1..10)
+
+    limit = div(before["total.allocated"], 2)
+    conn = configure(conn, ["maxmemory", Integer.to_string(limit)])
+
+    assert {{:simple, "OK"}, conn} = Client.command(conn, ["SET", "trigger", @payload])
+
+    {evicted, conn} = stats(conn)
+    freed = evicted["evicted.keys"]
+
+    assert freed >= 15 and freed <= 25
+    assert evicted["keys.count"] == 41 - freed
+    assert evicted["total.allocated"] < before["total.allocated"]
+    assert evicted["total.allocated"] <= limit + 2 * before["keys.bytes-per-key"]
+    assert evicted["oom.rejections"] == 0
+    assert Store.dbsize() == evicted["keys.count"]
+    assert Tracker.size(Tracker) == evicted["keys.count"]
+
+    assert {10, conn} = Client.command(conn, ["EXISTS" | keys(1..10)])
+    assert {cold, conn} = Client.command(conn, ["EXISTS" | keys(11..40)])
+    assert cold == 30 - freed
+
+    Aof.flush()
+    deletes = Aof.path() |> File.read!() |> String.split("$3\r\nDEL\r\n") |> length()
+    assert deletes - 1 == freed
+
+    {doctor, _conn} = Client.command(conn, ["MEMORY", "DOCTOR"])
+    assert doctor =~ "#{freed} keys have been evicted"
+  end
+
+  test "noeviction refuses growing writes but keeps freeing ones", %{conn: conn} do
+    conn = fill(conn, 1..30)
+    {before, conn} = stats(conn)
+    limit = div(before["total.allocated"], 2)
+    conn = configure(conn, ["maxmemory", Integer.to_string(limit)])
+
+    assert {@oom, conn} = Client.command(conn, ["SET", "blocked", @payload])
+    assert {0, conn} = Client.command(conn, ["EXISTS", "blocked"])
+    assert {@oom, conn} = Client.command(conn, ["APPEND", "key:1", "more"])
+    assert {@oom, conn} = Client.command(conn, ["RPUSH", "fresh-list", "value"])
+
+    assert {@payload, conn} = Client.command(conn, ["GET", "key:1"])
+    assert {30, conn} = Client.command(conn, ["DBSIZE"])
+
+    {blocked, conn} = stats(conn)
+    assert blocked["evicted.keys"] == 0
+    assert blocked["oom.rejections"] >= 3
+    assert blocked["total.allocated"] == before["total.allocated"]
+
+    assert {20, conn} = Client.command(conn, ["DEL" | keys(1..20)])
+    assert {{:simple, "OK"}, conn} = Client.command(conn, ["SET", "allowed", @payload])
+    assert {11, conn} = Client.command(conn, ["DBSIZE"])
+
+    {recovered, _conn} = stats(conn)
+    assert recovered["total.allocated"] < limit
+  end
+
+  test "maxmemory 0 lifts the limit again", %{conn: conn} do
+    conn = fill(conn, 1..20)
+    {before, conn} = stats(conn)
+    conn = configure(conn, ["maxmemory", Integer.to_string(div(before["total.allocated"], 2))])
+
+    assert {@oom, conn} = Client.command(conn, ["SET", "blocked", @payload])
+
+    conn = configure(conn, ["maxmemory", "0"])
+
+    assert {{:simple, "OK"}, conn} = Client.command(conn, ["SET", "blocked", @payload])
+    assert {21, _conn} = Client.command(conn, ["DBSIZE"])
+  end
+
+  test "a volatile policy with no TTL anywhere cannot free a thing", %{conn: conn} do
+    conn = configure(conn, ["maxmemory-policy", "volatile-lru", "maxmemory-samples", "64"])
+    conn = fill(conn, 1..20)
+
+    {before, conn} = stats(conn)
+    limit = div(before["total.allocated"], 2)
+    conn = configure(conn, ["maxmemory", Integer.to_string(limit)])
+
+    assert {@oom, conn} = Client.command(conn, ["SET", "blocked", @payload])
+    assert {20, conn} = Client.command(conn, ["DBSIZE"])
+
+    conn =
+      Enum.reduce(1..15, conn, fn index, acc ->
+        {1, acc} = Client.command(acc, ["EXPIRE", "key:#{index}", "600"])
+        acc
+      end)
+
+    assert {{:simple, "OK"}, conn} = Client.command(conn, ["SET", "allowed", @payload])
+
+    {after_, conn} = stats(conn)
+    assert after_["evicted.keys"] >= 10
+    assert after_["keys.count"] == 21 - after_["evicted.keys"]
+    assert {5, _conn} = Client.command(conn, ["EXISTS" | keys(16..20)])
+  end
+
+  test "a read refreshes access metadata only while a tracking policy is set", %{conn: conn} do
+    conn = fill(conn, 1..2)
+    assert Tracker.size(Tracker) == 0
+
+    conn = configure(conn, ["maxmemory-policy", "allkeys-lru"])
+    conn = fill(conn, 1..2)
+    assert Tracker.size(Tracker) == 2
+
+    Process.sleep(5)
+    conn = touch(conn, 1..1)
+
+    now = System.system_time(:millisecond)
+    assert Tracker.idleMs(Tracker, "key:1", now) < Tracker.idleMs(Tracker, "key:2", now)
+
+    conn = configure(conn, ["maxmemory-policy", "noeviction"])
+    Tracker.clear(Tracker)
+    _conn = touch(conn, 1..2)
+    assert Tracker.size(Tracker) == 0
+  end
+
+  test "a sweep drops metadata for keys that are gone", %{conn: conn} do
+    conn = configure(conn, ["maxmemory-policy", "allkeys-lru"])
+    conn = fill(conn, 1..10)
+    assert Tracker.size(Tracker) == 10
+
+    assert {5, conn} = Client.command(conn, ["DEL" | keys(1..5)])
+    assert Tracker.size(Tracker) == 10
+
+    conn = configure(conn, ["maxmemory", "1gb"])
+    assert {{:simple, "OK"}, conn} = Client.command(conn, ["SET", "fresh", "value"])
+
+    assert Store.dbsize() == 6
+    assert Tracker.size(Tracker) == 6
+    {reported, _conn} = stats(conn)
+    assert reported["tracker.keys"] == 6
+    assert reported["evicted.keys"] == 0
+  end
+
+  defp configure(conn, args) do
+    {{:simple, "OK"}, conn} = Client.command(conn, ["CONFIG", "SET" | args])
+    conn
+  end
+
+  defp fill(conn, range) do
+    Enum.reduce(range, conn, fn index, acc ->
+      {{:simple, "OK"}, acc} = Client.command(acc, ["SET", "key:#{index}", @payload])
+      acc
+    end)
+  end
+
+  defp touch(conn, range) do
+    Enum.reduce(range, conn, fn index, acc ->
+      {@payload, acc} = Client.command(acc, ["GET", "key:#{index}"])
+      acc
+    end)
+  end
+
+  defp keys(range), do: Enum.map(range, &"key:#{&1}")
+
+  defp stats(conn) do
+    {flat, conn} = Client.command(conn, ["MEMORY", "STATS"])
+    {flat |> Enum.chunk_every(2) |> Map.new(fn [name, value] -> {name, value} end), conn}
+  end
+end