lotusdb

type ColumnFamily struct {
	// contains filtered or unexported fields
}

type ColumnFamilyOptions struct {

	// CfName column family name, can`t be nil.
	CfName string

	// DirPath dir path for column family, default value is db path+CfName .
	// will be created automatically if not exist.
	DirPath string

	// MemtableSize represents the maximum size in bytes for a memtable.
	// It means that each memtable will occupy so much memory.
	// Default value is 64MB.
	MemtableSize uint32

	// MemtableNums represents maximum number of memtables to keep in memory before flushing.
	// Default value is 5.
	MemtableNums int

	// MemSpaceWaitTimeout represents timeout for waiting enough memtable space to write.
	// In this scenario will wait: memtable has reached the maximum nums, and has no time to be flushed into disk.
	// Default value is 100ms.
	MemSpaceWaitTimeout time.Duration

	// IndexerDir dir path to store index meta data, default value is dir path.
	IndexerDir string

	// FlushBatchSize Since we use b+tree to store index info on disk right now.
	// We need flush data to b+tree in batches, which can minimize random IO and reduce write amplification.
	// Default value is 100000.
	FlushBatchSize int

	// WalMMap represents whether to use memory map for reading and writing on WAL.
	// Setting false means to use standard file io.
	// Default value is false.
	WalMMap bool

	// WalBytesFlush can be used to smooth out write I/Os over time. Users shouldn't rely on it for persistency guarantee.
	// Default value is 0, turned off.
	WalBytesFlush uint32

	// ValueLogDir dir path to store value log file, default value is dir path.
	ValueLogDir string

	// ValueLogFileSize size of a single value log file.
	// Default value is 1GB.
	ValueLogFileSize int64

	// ValueLogMmap similar to WalMMap, default value is false.
	ValueLogMmap bool

	// ValueLogGCRatio if discarded data in value log exceeds this ratio, it can be picked up for compaction(garbage collection)
	// And if there are many files reached the ratio, we will pick the highest one by one.
	// The recommended ratio is 0.5, half of the file can be compacted.
	// Default value is 0.5.
	ValueLogGCRatio float64

	// ValueLogGCInterval a background groutine will check and do gc periodically according to the interval.
	// If you don`t want value log file be compacted, set it a Zero time.
	// Default value is 10 minutes.
	ValueLogGCInterval time.Duration
}

type LotusDB struct {
	// contains filtered or unexported fields
}

type Options struct {
	// DBPath db path, will be created automatically if not exist.
	DBPath string

	// CfOpts options for column family.
	CfOpts ColumnFamilyOptions
}

type Stat struct {
	MemtableSize int64
}

type WriteOptions struct {

	// Default value is false.
	Sync bool

	// DisableWal if true, writes will not first go to the write ahead log, and the write may get lost after a crash.
	// Setting true only if don`t care about the data loss.
	// Default value is false.
	DisableWal bool

	// ExpiredAt time to live for the specified key, must be a time.Unix value.
	// It will be ignored if it`s not a positive number.
	// Default value is 0.
	ExpiredAt int64
}