Batch example creating a bucket and putting a value in one call?

[tvmaly]

could you add an example of a call to Batch that shows a bucket being created and a value being added in one call?

[xiang90]

@tvmaly You can create a tx, and insert multiple kv pairs to batch updates.

See https://github.com/boltdb/bolt/blob/master/cmd/bolt/main.go#L1042-L1065 for example.

[lnshi]

@xiang90 But in the code never touch the db.Batch API, I also want an example to demonstrate how to use the db.Batch API properly, can you help with that? Thanks.

Oh, it seems db.Batch is just a helper method, if you create a tx, and insert multiple kv pairs then it is already a so called batch.

And read from the document:

Concurrent Batch calls are opportunistically combined into larger transactions. Batch is only useful when there are multiple goroutines calling it.

2. the function passed to Batch may be called multiple times, regardless of whether it returns error or not.

that means If I do multiple insertions in the db.Batch, then call it multiple times from different goroutines, and use NextSequence style keys, then there is a chance my docs get inserted multiple times?

@benbjohnson can u help to verify am I correct?

[wanderingeek]

+1

Would really appreciate some examples and best practices on the use of the db.Batch() method.

[atedja]

Need confirmation from BoltDB developers. The way I understand it, calling Batch() concurrently combines the transactions into one larger one, sort-of the same effect if it were to put all the code together under one large Update(). Basically it allows non-blocking writes, useful in cases where you know you are inserting large amount of data at once.

Here's a question: What if one of them fails? Does this mean the rest of the calls also fail with no way to determine which ones are failing?

Edit: Okay, I am seeing that the failed ones are ignored, and Batch() under the hood is a multiple Update() calls https://github.com/boltdb/bolt/blob/fa5367d20c994db73282594be0146ab221657943/db.go#L704