Re: LMDB: iterating over the whole DB

Vladimír Čunát wrote:

On 8/19/20 7:11 PM, Howard Chu wrote:

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We have a process that needs to analyze the contents of a whole LMDB. So far the approach was to open a read-only transaction and use a cursor to iterate over the whole contents in order. This long transaction apparently causes other concurrent process(es) to get MDB_MAP_FULL from mdb_put() even though that LMDB has plenty free pages at that moment.

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It's a documented feature.

I haven't seen that in docs http://www.lmdb.tech/doc/%C2%A0 (I even skimmed the "internals" section)  Am I missing some part?

You definitely need to read more carefully. It's on the very first page of your link, under Caveats.

"Avoid long-lived transactions." ...