10.02.2022 20:18, Adriano dos Santos Fernandes wrote:
We should have better strategy for request cache inside the statement. If they are cheap to create, it would make no sense to never destroy them like now.
Looking at Statement::getRequest() I see it as dirty cheap, just a matter of few allocations.
I would calculate size of statement as sum of DSQL statement pool + JRD statement pool after it is prepared.
Sounds reasonable.
Please note that requests (both DSQL and JRD) are also created from the statement pools. But if there are active requests, I think the statement should not even be considered to be taken out of cache. It's necessary in this case, so in reality it does not use cache space. So I think cache size (to remove least recent used) should not consider active (necessary) statements.
Getting rid of long-running but rare statements may be useful. If we speak LRU, then the cached statement should be stamped when a new child request is created. So we may defer "uncaching" of active request until it's freed by user (if its statement weren't re-stamped in the meantime). It's size should not be taken into account, as you say.
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