I have use the DynamoDB for a while.
And was told that my hashkeys to insert are not so uniformly, there was a hot spot in a partition.
May I have the hash algorithm to judge my hashkeys?
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Usually, hot spots are caused by single hot keys so knowing the hash algorithm might not help much. Is it possible for you to log the hash keys in your requests and count the accesses?Johnny Wu– Johnny Wu2015-02-18 00:12:45 +00:00Commented Feb 18, 2015 at 0:12
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1 Answer
DynamoDB does not expose their internal hashing algorithm but that should not affect your hash key distribution. A good hashing algorithm will randomly distribute your hash key values (i.e. "key1" and "key2" will hash to 2 strings that are not correlated to each other in any way).
If you are suffering from hot key issues in your DynamoDB table, it likely means you are accessing one hash key (or a small range of hash keys) more frequently than others, or that your hash key values are not distributed enough (i.e. not enough unique values).
Where did you get the information regarding hot spot in your partition? It may be helpful to go back to that source and dig more into the details of the unevenly distributed hashkey values.
3 Comments
Zagfai
I want to know how dynamo hashing the key, whether they just pick the first character of my hashkey, or do like md5(hashkey) for distributing.
Daniela Miao
I imagine it's the entire hashkey since that's the only way to ensure it's a correct hashing function.
Zagfai
Yeah, I do think so, but nothing supports our ideas.