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Re: LMDB mdb_dbi_open mystery



Thanks for the reply.

That's what it says on its own, but the doc also says:

* The database handle will be private to the current transaction until
* the transaction is successfully committed. If the transaction is
* aborted the handle will be closed automatically.
* After a successful commit the handle will reside in the shared
* environment, and may be used by other transactions.

That suggests I have to wait for a transaction to finish before I can reuse the same db handle for other transactions.

How would you in practice perform multiple transactions at the same time? I don't see it yet. I'm missing something basic.


Feb 11, 2019, 5:50 AM by hyc@symas.com:
Sam Dave wrote:
Hello,

The doc for mdb_dbi_open says:

* This function must not be called from multiple concurrent
* transactions in the same process. A transaction that uses
* this function must finish (either commit or abort) before
* any other transaction in the process may use this function.

This indicates that each process can only perform one transaction at the same time.

No, it only says you may only call mdb_dbi_open from one transaction at a time.
This makes sense for write transactions, but wasn't LMDB supposed to support multiple read transactions at the same time?

I'm a bit confused now. Can you assist?

Thanks,
Sam


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-- Howard Chu
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