e9eda7e7c8
* cache: add sharded cache implementation Add Cache impl and a few tests. This cache is 256-way sharded, mainly so each shard has it's own lock. The main cache structure is a readonly jump plane into the right shard. This should remove the single lock contention on the main lock and provide more concurrent throughput - Obviously this hasn't been tested or measured. The key into the cache was made a uint32 (hash.fnv) and the hashing op is not using strings.ToLower anymore remove any GC in that code path. * here too * Minimum shard size * typos * blurp * small cleanups no defer * typo * Add freq based on Johns idea * cherry-pick conflict resolv * typo * update from early code review from john * add prefetch to the cache * mw/cache: add prefetch * remove println * remove comment * Fix tests * Test prefetch in setup * Add start of cache * try add diff cache options * Add hacky testcase * not needed * allow the use of a percentage for prefetch If the TTL falls below xx% do a prefetch, if the record was popular. Some other fixes and correctly prefetch only popular records.
85 lines
1.8 KiB
Go
85 lines
1.8 KiB
Go
/*
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Copyright 2012 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package singleflight
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import (
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"errors"
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"fmt"
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"sync"
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"sync/atomic"
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"testing"
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"time"
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)
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func TestDo(t *testing.T) {
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var g Group
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v, err := g.Do(1, func() (interface{}, error) {
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return "bar", nil
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})
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if got, want := fmt.Sprintf("%v (%T)", v, v), "bar (string)"; got != want {
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t.Errorf("Do = %v; want %v", got, want)
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}
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if err != nil {
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t.Errorf("Do error = %v", err)
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}
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}
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func TestDoErr(t *testing.T) {
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var g Group
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someErr := errors.New("Some error")
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v, err := g.Do(1, func() (interface{}, error) {
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return nil, someErr
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})
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if err != someErr {
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t.Errorf("Do error = %v; want someErr", err)
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}
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if v != nil {
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t.Errorf("unexpected non-nil value %#v", v)
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}
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}
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func TestDoDupSuppress(t *testing.T) {
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var g Group
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c := make(chan string)
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var calls int32
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fn := func() (interface{}, error) {
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atomic.AddInt32(&calls, 1)
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return <-c, nil
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}
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const n = 10
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var wg sync.WaitGroup
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for i := 0; i < n; i++ {
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wg.Add(1)
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go func() {
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v, err := g.Do(1, fn)
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if err != nil {
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t.Errorf("Do error: %v", err)
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}
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if v.(string) != "bar" {
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t.Errorf("got %q; want %q", v, "bar")
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}
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wg.Done()
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}()
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}
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time.Sleep(100 * time.Millisecond) // let goroutines above block
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c <- "bar"
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wg.Wait()
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if got := atomic.LoadInt32(&calls); got != 1 {
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t.Errorf("number of calls = %d; want 1", got)
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}
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}
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