David Ribeiro Alves has posted comments on this change. (
Change subject: KUDU-1704: add c++ client support for READ_YOUR_WRITES mode
Patch Set 10:
PS10, Line 186:
> Right, so KuduScanner::Open is called after this, and at that point it grab
RYW with scan tokens is a bit of a fuzzy concept, since RYW is by definition
local and scan tokens are by definition multi client.
If I understand the suggestion, the point is that to get RYW in the point of
view of the scan token emitter, we could safely ignore the scan token's
receiver client's internal last propagated timestamp, which might be more
I think things get murky here a bit, since RYW with scan tokens are murky. I
don't think it would necessarily be wrong to do that, but I think it makes
reasoning about timestamps and how they get propagated a bit harder if we have
two ways to choose the lower bound for the RYW scan. Moreover, in practice, I
suspect it's very rarely the case that an active client is permanently being
written to and read from (using scan tokens).
My suggestion is to keep the path simple and the same as for the local scans.
Maybe note somewhere that is a possible optimization if we ever notice scan
token RYW reads stalling.
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Gerrit-Owner: Hao Hao <hao....@cloudera.com>
Gerrit-Reviewer: Alex Rodoni <arod...@cloudera.com>
Gerrit-Reviewer: Dan Burkert <danburk...@apache.org>
Gerrit-Reviewer: David Ribeiro Alves <davidral...@gmail.com>
Gerrit-Reviewer: Hao Hao <hao....@cloudera.com>
Gerrit-Reviewer: Kudu Jenkins
Gerrit-Reviewer: Mike Percy <mpe...@apache.org>
Gerrit-Reviewer: Tidy Bot
Gerrit-Comment-Date: Fri, 02 Mar 2018 23:01:02 +0000