CODEWITHSUNDEEP
androidsnappydb
kirvel
kirvel

Reputation: 671

What does byBatch(size) mean in SnappyDB?

for (String[] batch : snappyDB.allKeysIterator().byBatch(0))

What does 'size' param mean in byBatch() method?

Upvotes: 0

Views: 47

Answers (2)

Razvan S.
Razvan S.

Reputation: 803

According to SnappyDB documentation, found here:

Iterable<String[]> byBatch(int size);// Get an iterable of key batch, each batch of maximum [size] keys.

So size specifies the maximum number of keys for each batch. However, according to the documentation:

Please note that you should use the byBatch iterable to process all keys only on large collections. On reasonably small collections, using the array based APIs (findKeys and findKeysBetween) with the form for (String key : db.findKeys("android")) is a lot more efficient. Iterators should only be used to process large collections or for collection paging view / access.

So make sure that you really need byBatch in your use case.

Upvotes: 0

JensV
JensV

Reputation: 4544

Without using byBatch you will only have a KeyIterator which does not implement Iterator or Iterable so you can't use it in a loop.

byBatch(n) creates a BatchIterable which is Iterable and an Iterator. It basically just calls next(n) on the KeyIterator when you call next() on it. (Source)

KeyIterator#next(int max) seems to always attempt to fetch max elements from the Database. So I presume you will most likely have max elements in the batch array from your example on each iteration. So it doesn't make much sense to pass 0 as you're doing (not sure if that even works).

Also just reading the README from the GitHub repo reveals some documentation:

Iterable<String[]> byBatch(int size); // Get an iterable of key batch, each batch of maximum [size] keys.

Upvotes: 0

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