What is the relationship between Primary Index and Keys? Are digest store on SSD?

The primary index keeps metadata about those records which are stored on the Aerospike cluster node. Each record’s metadata takes exactly 64B of DRAM in the primary index. A node only indexes its own records. What it knows about the other nodes is just the partition map - which node it needs to talk…

Does it mean that primary index consists of Key, index metadata, and digest?

The primary index always lives in memory, regardless of where the namespace stores its data. Each record has an index entry in the primary index, which costs 64B of DRAM. Of that 64B, 20B are for the digest, and the other bits and bytes are used for other metadata , such as expiration (void) time, ge…

Ok, the primary index which always lives in memory does not contain primary key (key). It consists of metadata and digest. Am I right?

That’s right. By default Aerospike only stores the digest. There’s a write policy for all the clients which can tell the server to store the key (in your application). It gets stored with the rest of the record’s data, not in the primary index. Since the key can be large (UUIDs are 36 bytes, for exa…

You’re welcome. Yes, the 64B in the primary index entry is also stored on SSD, along with the record data. This is needed for rebuilding the primary index on cold restart . See the capacity planning guide for more information about storage and memory consumption.

Primary Index

General Discussion

milotic91 February 6, 2018, 6:34am 7

Thanku rbotzer, it is very much clear that primary index does not store keys, it only stores digest. Does digest is also stored on SSD along with data?

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Primary Index

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