Best Practices

The following are best practices for developing HSE applications. Many of these are covered in greater detail in the discussion of HSE concepts.

Keys and KVSs

Use a segmented key in the common case where related sets of KV pairs in a KVS are accessed together. Choose a key prefix that groups related KV pairs when keys are sorted lexicographically, and always create the KVS storing these KV pairs with a prefix.length equal to the key prefix length.

Use a different KVS for each collection of KV pairs requiring its own segmented key structure.

Create index KVSs to efficiently implement query patterns that cannot be supported with a single segmented key prefix.

Use an unsegmented key in the case where there is no relationship between KV pairs in a KVS, and always create the KVS storing these KV pairs with a prefix.length of zero (0).

Cursors and Gets

Always use get operations when iteration is not required. Gets are significantly faster than cursor seeks.

Use non-transaction cursors for most applications. Transaction cursors exist to support some specialized use cases and incur additional overhead.

Transactions

Use transactions when required for application correctness. Otherwise, for best performance open a KVS with transactions disabled (transactions.enabled=false) and use non-transaction operations.

Application Lifecycle

At application startup, call hse_init() to initialize the HSE subsystem within your application. This function should be called only once. From there you can create or open a KVDB and its associated KVSs and perform KV operations.

At application shutdown, close all KVSs for a KVDB before closing that KVDB. After all KVDBs are closed, call hse_fini() to completely shutdown the HSE subsystem within your application. Using a signal handler to close resources can also be helpful when trying to handle unexpected application shutdown.