eth/fetcher: don't skip block/header when parent is not found #633
+116
−37
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Currently, we simply skip importing block/header when parent block/header is not found. However, since multiple blocks can be imported in parallel, the not found parent might be due to the fact that the parent import does not finish yet. This leads to a suitation that the correct block in canonical chain is skipped and the node gets stuck until the peer timeout. We observe this behavior when there are reorgs and block import is time consuming.
This commit fixes it by creating a new queue for those missing parent blocks and re-import them after the parent is imported.