Redis Why does a set use a hashtable instead of a hash structure using a ziplist and then using a hashtable when the data reaches a certain magnitude

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Comment From: sundb

For my personal opinions. 1. ziplist(listpack) has less memory overhead than dict, which can save huge memory for a large number of small hash. 2. ziplist(listpack) memory is contiguous, more cache friendly, for small hashes, ziplist(listpack) is faster. 3. ziplist(lipstack) stores different encoding according to the value, it will save memory than storing the string directly(dict)

Comment From: sundb

@Janmsstrive As i mentioned above, ziplist(listpack) is only faster with small values and small size, when the size or the number of hash reaches the threshold, its performance will drop.

Comment From: Janmsstrive

For my personal opinions.

1. ziplist(listpack) has less memory overhead than dict, which can save huge memory for a large number of small hash.
2. ziplist(listpack) memory is contiguous, more cache friendly, for small hashes, ziplist(listpack) is faster.
3. ziplist(lipstack) stores different encoding according to the value, it will save memory than storing the string directly(dict)

Why does the hash structure use ziplist, wait for the data to reach a certain magnitude and then use hashtable

As i mentioned above, ziplist(listpack) is only faster with small values and small size, when the size or the number of hash reaches the threshold, its performance will drop

You can use ziplist for a set and then you can use a hashtable, and that's how you use hash

Comment From: sundb

Ohh, sorry for my misunderstanding, Look like #11290 is what you want.

Comment From: Janmsstrive

Ohh, sorry for my misunderstanding, Look like #11290 is what you want.

thanks

Comment From: zuiderkwast

I guess #11290 answers this question, so this can be closed?