Go

Mon, 02 Mar 2026 17:44:21 +0800

draft need to be improved

Slice

type slice struct {
 array unsafe.Pointer
 len int
 cap int
}
// 扩容
func nextslicecap(newLen, oldCap int) int {
 newcap := oldCap
 doublecap := newcap + newcap
 if newLen > doublecap {
 return newLen
 }
 const threshold = 256
 if oldCap < threshold {
 return doublecap
 }
 for {
 // 1.25x
 newcap += (newcap + 3*threshold) >> 2
 if uint(newcap) >= uint(newLen) {
 break
 }
 }
 // overflowed
 if newcap <= 0 {
 return newLen
 }
 return newcap
}

Map

type Map struct {

 used uint64 // The number of filled slots
 seed uintptr // the hash seed, computed as a unique random number per map.

 // The directory of tables.
 // Normally dirPtr points to an array of table pointers
 // dirPtr *[dirLen]*table
 dirPtr unsafe.Pointer

 dirLen int // 1 << globalDepth
 globalDepth uint8 // The number of bits to use in table directory lookups.
 globalShift uint8 // The number of bits to shift out, 64 - globalDepth
 writing uint8 // detect the race.
 tombstonePossible bool // whether a table in this map contains a tombstone.
 clearSeq uint64 // version number, used to detect map clears during iteration.
}

Swiss Table

refer: Faster Go maps with Swiss Tables

Redis Datastructure

Thu, 12 Feb 2026 09:52:26 +0800

Redis 数据结构

逻辑类型 (Type)	底层数据结构 (Internal Encoding)
String	int, embstr, raw (SDS)
List	quicklist
Hash	listpack, hashtable
Set	intset, hashtable
ZSet	listpack, skiplist + hashtable

graph TD A[redisObject] --> B{type} B -->|STRING| C[int / embstr / raw] B -->|LIST| D[quicklist] B -->|HASH| E{size?} B -->|SET| F{all int?} B -->|ZSET| G{size?} E -->|小| H[listpack] E -->|大| I[hashtable] F -->|yes & 少| J[intset] F -->|no| K[hashtable] G -->|小| L[listpack] G -->|大| M[skiplist + hashtable]

每种类型根据数据量自动切换编码：小数据用紧凑结构省内存，大数据切高效结构保性能。

源码分析 on 我的技术博客

Go

Slice

Map

Swiss Table

Redis Datastructure

Redis 数据结构