write_batch_pool.go

// Copyright (c) 2018 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package writes

import (
	"github.com/m3db/m3/src/x/pool"
)

const (
	// defaultInitialiBatchSize determines the initial batch size that will be used when filling up the
	// pool.
	defaultInitialBatchSize = 1024
	// defaultWritePoolMaxBatchSize is the default maximum size for a writeBatch that the pool
	// will allow to remain in the pool. Any batches larger than that will be discarded to prevent
	// excessive memory use forever in the case of an exceptionally large batch write.
	defaultMaxBatchSize = 100000
)

// WriteBatchPool is a pool of WriteBatch.
type WriteBatchPool struct {
	pool             pool.ObjectPool
	initialBatchSize int
	maxBatchSize     int
}

// NewWriteBatchPool constructs a new WriteBatchPool.
func NewWriteBatchPool(
	opts pool.ObjectPoolOptions,
	initialBatchSizeOverride,
	maxBatchSizeOverride *int,
) *WriteBatchPool {
	initialBatchSize := defaultInitialBatchSize
	if initialBatchSizeOverride != nil {
		initialBatchSize = *initialBatchSizeOverride
	}

	maxBatchSize := defaultMaxBatchSize
	if maxBatchSizeOverride != nil {
		maxBatchSize = *maxBatchSizeOverride
	}

	p := pool.NewObjectPool(opts)
	return &WriteBatchPool{pool: p, initialBatchSize: initialBatchSize, maxBatchSize: maxBatchSize}
}

// Init initializes a WriteBatchPool.
func (p *WriteBatchPool) Init() {
	p.pool.Init(func() interface{} {
		return NewWriteBatch(p.initialBatchSize, nil, p.Put)
	})
}

// Get retrieves a WriteBatch from the pool.
func (p *WriteBatchPool) Get() WriteBatch {
	w := p.pool.Get().(WriteBatch)
	return w
}

// Put stores a WriteBatch in the pool.
func (p *WriteBatchPool) Put(w WriteBatch) {
	if w.cap() > p.maxBatchSize {
		// WriteBatch has grown too large to remain in the pool.
		return
	}

	p.pool.Put(w)
}