Read redis Data Structure

1. dict

There are two main problems:

1. Hash conflicts. The solution is zip.

Typedef struct dictentry {void * key; Union {void * val; uint64_t u64; int64_t s64 ;}v; struct dictentry * Next;} dictentry;

Next field zip

2. rehash during resizing, similar to copy on write

Typedef struct dict {dicttype * type; void * privdata; dictht HT [2]; int rehashidx;/* rehashing not in progress if rehashidx =-1 */INT iterators; /* Number of iterators currently running */} dict;

HT [0] stores data when resizing is not completed. Ht [1] stores data after resizing. If you need to resize a hash table, any operation on the hash table will find a key rehash from HT [0] And put it in HT [1]. gradually put the data in HT [0] into HT [1]. After all the rehash data in HT [0] is completed, the space is released. Ht [0] points to HT [1].