paging

Documentation

Index

• Constants
• func CalculateSeekCnt(expectCnt uint64) float64
• func GrowPagingSize(size uint64, maxv uint64) uint64

Constants

const (
	MinPagingSize uint64 = 128

	MaxPagingSize = 50000

	Threshold uint64 = 960
)

A paging request may be separated into multi requests if there are more data than a page. The paging size grows from min to max. See https://github.com/pingcap/tidb/issues/36328 e.g. a paging request scans over range (r1, r200), it requires 128 rows in the first batch, if it's not drained, then the paging size grows, the new range is calculated like (r100, r200), then send a request again. Compare with the common unary request, paging request allows early access of data, it offers a streaming-like way processing data.

Functions

func CalculateSeekCnt

func CalculateSeekCnt(expectCnt uint64) float64

CalculateSeekCnt calculates the seek count from expect count

func GrowPagingSize

func GrowPagingSize(size uint64, maxv uint64) uint64

GrowPagingSize grows the paging size and ensures it does not exceed MaxPagingSize