Location of published stream items

Question

Hi

I wanted to know how the data is stored in multichain. Had two questions:

1.  When I publish some key-value pair to stream (say some 10mb data), is the entire data stored in the blockchain? Or is this data stored in some database and a pointer to the data kept in the blockchain?

2. Where is the transaction object corresponding to the published item stored?

Answer 1

The entire data is stored in the blockchain, at least in current versions of MultiChain. The transaction object corresponding to the item is also stored in the blockchain – indeed the item itself is represented as metadata for that transaction.

Comments

Got it! A related question, if all the data is stored in the blockchain, how is the search for streams done? Suppose I have two streams; 'stream1' and 'stream2' with some data. When I query for items from stream1, how is this search performed?

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If a node is subscribed to a stream, e.g. stream1, then it is indexing all of that stream's items in real time. And this index keeps each stream's item separate.