buffer

Documentation

Overview

Package buffer provides buffer pool management for XxSql storage engine.

Index

• type BufferFrame
• type BufferPool
  • func NewBufferPool(config BufferPoolConfig) *BufferPool
  • func (bp *BufferPool) Clear() error
  • func (bp *BufferPool) DeletePage(id page.PageID) error
  • func (bp *BufferPool) FlushAll() error
  • func (bp *BufferPool) FlushPage(id page.PageID) error
  • func (bp *BufferPool) GetPage(id page.PageID) (*page.Page, error)
  • func (bp *BufferPool) IsDirty(id page.PageID) bool
  • func (bp *BufferPool) MarkDirty(id page.PageID)
  • func (bp *BufferPool) NewPage() (*page.Page, error)
  • func (bp *BufferPool) PinPage(id page.PageID) error
  • func (bp *BufferPool) SetDiskManager(dm DiskManager)
  • func (bp *BufferPool) Size() int
  • func (bp *BufferPool) Stats() BufferPoolStats
  • func (bp *BufferPool) UnpinPage(id page.PageID, isDirty bool) error
• type BufferPoolConfig
• type BufferPoolStats
  • func (s BufferPoolStats) HitRate() float64
• type DiskManager

Types

type BufferFrame

type BufferFrame struct {
	Page     *page.Page
	PinCount int32
	Dirty    bool
	Element  *list.Element // LRU list element
}

BufferFrame represents a frame in the buffer pool.

type BufferPool

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

BufferPool manages a pool of cached pages.

func NewBufferPool

func NewBufferPool(config BufferPoolConfig) *BufferPool

NewBufferPool creates a new buffer pool.

func (*BufferPool) Clear

func (bp *BufferPool) Clear() error

Clear removes all pages from the buffer pool.

func (*BufferPool) DeletePage

func (bp *BufferPool) DeletePage(id page.PageID) error

DeletePage removes a page from the buffer pool.

func (*BufferPool) FlushAll

func (bp *BufferPool) FlushAll() error

FlushAll flushes all dirty pages to disk.

func (*BufferPool) FlushPage

func (bp *BufferPool) FlushPage(id page.PageID) error

FlushPage flushes a specific page to disk.

func (*BufferPool) GetPage

func (bp *BufferPool) GetPage(id page.PageID) (*page.Page, error)

GetPage retrieves a page from the buffer pool or loads it from disk.

func (*BufferPool) IsDirty

func (bp *BufferPool) IsDirty(id page.PageID) bool

IsDirty returns whether a page is dirty.

func (*BufferPool) MarkDirty

func (bp *BufferPool) MarkDirty(id page.PageID)

MarkDirty marks a page as dirty.

func (*BufferPool) NewPage

func (bp *BufferPool) NewPage() (*page.Page, error)

NewPage creates a new page and adds it to the buffer pool.

func (*BufferPool) PinPage

func (bp *BufferPool) PinPage(id page.PageID) error

PinPage increments the pin count of a page.

func (*BufferPool) SetDiskManager

func (bp *BufferPool) SetDiskManager(dm DiskManager)

SetDiskManager sets the disk manager.

func (*BufferPool) Size

func (bp *BufferPool) Size() int

Size returns the number of pages in the buffer.

func (*BufferPool) Stats

func (bp *BufferPool) Stats() BufferPoolStats

Stats returns buffer pool statistics.

func (*BufferPool) UnpinPage

func (bp *BufferPool) UnpinPage(id page.PageID, isDirty bool) error

UnpinPage decrements the pin count of a page.

type BufferPoolConfig

type BufferPoolConfig struct {
	PoolSize    int
	PageSize    int
	DiskManager DiskManager
}

BufferPoolConfig holds buffer pool configuration.

type BufferPoolStats

type BufferPoolStats struct {
	PoolSize    int    `json:"pool_size"`
	PageCount   int    `json:"page_count"`
	DirtyPages  int    `json:"dirty_pages"`
	PinnedPages int    `json:"pinned_pages"`
	Hits        uint64 `json:"hits"`
	Misses      uint64 `json:"misses"`
	Evictions   uint64 `json:"evictions"`
}

BufferPoolStats holds buffer pool statistics.

func (BufferPoolStats) HitRate

func (s BufferPoolStats) HitRate() float64

HitRate returns the buffer pool hit rate.

type DiskManager

type DiskManager interface {
	ReadPage(id page.PageID) (*page.Page, error)
	WritePage(p *page.Page) error
	AllocatePage() (page.PageID, error)
	DeallocatePage(id page.PageID) error
}

DiskManager provides disk I/O operations for the buffer pool.