config.go

package rosedb

import (
	"github.com/roseduan/rosedb/storage"
)

// DataIndexMode the data index mode.
type DataIndexMode int

const (
	// KeyValueMemMode key and value are both in memory, read operation will be very fast in this mode.
	// Because there is no disk seek, just get value from the corresponding data structures in memory.
	// This mode is suitable for scenarios where the value are relatively small.
	KeyValueMemMode DataIndexMode = iota

	// KeyOnlyMemMode only key in memory, there is a disk seek while getting a value.
	// Because the value is in db file.
	KeyOnlyMemMode
)

const (
	// DefaultAddr default rosedb server address and port.
	DefaultAddr = "127.0.0.1:5200"

	// DefaultDirPath default rosedb data dir.
	DefaultDirPath = "/tmp/rosedb_server"

	// DefaultBlockSize default db file size: 16mb.
	// If reach the size, db file will never opening for writing.
	DefaultBlockSize = 16 * 1024 * 1024

	// DefaultMaxKeySize default max key size: 128 bytes.
	DefaultMaxKeySize = uint32(128)

	// DefaultMaxValueSize default max value size: 1mb.
	DefaultMaxValueSize = uint32(1 * 1024 * 1024)

	// DefaultReclaimThreshold default disk reclaim threshold: at least 4 archived db files.
	DefaultReclaimThreshold = 4
)

// Config the config options of rosedb.
type Config struct {
	Addr         string               `json:"addr" toml:"addr"`             // server address
	DirPath      string               `json:"dir_path" toml:"dir_path"`     // rosedb dir path of db file
	BlockSize    int64                `json:"block_size" toml:"block_size"` // each db file size
	RwMethod     storage.FileRWMethod `json:"rw_method" toml:"rw_method"`   // db file read and write method
	IdxMode      DataIndexMode        `json:"idx_mode" toml:"idx_mode"`     // data index mode
	MaxKeySize   uint32               `json:"max_key_size" toml:"max_key_size"`
	MaxValueSize uint32               `json:"max_value_size" toml:"max_value_size"`

	// Sync is whether to sync writes from the OS buffer cache through to actual disk.
	// If false, and the machine crashes, then some recent writes may be lost.
	//
	// Note that if it is just the process that crashes (and the machine does not) then no writes will be lost.
	//
	// The default value is false.
	Sync bool `json:"sync" toml:"sync"`

	ReclaimThreshold int `json:"reclaim_threshold" toml:"reclaim_threshold"` // threshold to reclaim disk
}

// DefaultConfig get the default config.
func DefaultConfig() Config {
	return Config{
		Addr:             DefaultAddr,
		DirPath:          DefaultDirPath,
		BlockSize:        DefaultBlockSize,
		RwMethod:         storage.FileIO,
		IdxMode:          KeyValueMemMode,
		MaxKeySize:       DefaultMaxKeySize,
		MaxValueSize:     DefaultMaxValueSize,
		Sync:             false,
		ReclaimThreshold: DefaultReclaimThreshold,
	}
}