[Minor bug / minor fix] TxPool - fix inconsistent counters (estimators) #1842
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storage/txcache/txByHashMap.go
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| // we might end up decrementing the counters twice. | ||
| // Possible solution: use an "onItemRemoved" callback in the "backingMap" | ||
| // to decrement the counters. | ||
| tx := item.(*WrappedTransaction) |
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You can check for correct type assertion here, so if will be the case in some strange circumstances you will avoid passing nil to line 46 in estimateTxSize method and also to return nil, true in line 49
tx, ok := item.(*WrappedTransaction)
if !ok {
return nil, false
}
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Changed. Though, having something other than *WrappedTransaction in the backingMap would be a critical bug.
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Agreed. But for the sake of uncle Bob :)
SebastianMarian
approved these changes
Jun 1, 2020
AdoAdoAdo
approved these changes
Jun 1, 2020
LucianMincu
approved these changes
Jun 1, 2020
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Original conversation in PR 1802.
Fixed some inconsistent counters for senders and transactions within the internal structures of the transactions pool. Inconsistencies could occur in case of high concurrency and / or concurrent removals (eviction plus removal due to commit / finalize). The bug was mostly benign, but if it were, say, thousands of such events, the counters would have become slightly off and therefore could have lead - in extreme cases - to OOM (since eviction would have been based on bad, low counters).
Extra - fixed some linting issues within package
storage/immunitycache.Details of the fix:
txListBySenderMap.addSender(): counter is consistent because the function is called undertxListBySenderMap's global mutextxListBySenderMap.removeSender(): fixedtxByHashMap.addTx(): counter is consistent because we use "SetIfAbsent"txByHashMap.removeTx(): fixed