Details
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Bug
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Resolution: Fixed
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Critical
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6.5.0
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Triaged
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Unknown
Description
Currently on a topology change we reset the high prepared seqno of the active node. This happens because of the code here http://src.couchbase.org/source/xref/trunk/kv_engine/engines/ep/src/durability/active_durability_monitor.cc#691-692. Believe this is also an issue if we do an active->replica/pending issue where the new passiveDM will not have a correct HPS.
Below test case is a simple reproduction.
TEST_P(ActiveDurabilityMonitorTest, HPSResetOnTopologyChange) {
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// To start, we have 1 chain with active and replica1
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addSyncWrite(1);
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{
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SCOPED_TRACE("");
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assertNumTrackedAndHPS(1, 1);
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}
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// Should commit on replica1 ack.
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testSeqnoAckReceived(replica1,
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1 /*ackSeqno*/,
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0 /*expectedNumTracked*/,
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1 /*expectedLastWriteSeqno*/,
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1 /*expectedLastAckSeqno*/);
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{
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SCOPED_TRACE("");
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assertNumTrackedAndHPS(0, 1);
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}
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// Add the secondChain with the new node
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EXPECT_NO_THROW(getActiveDM().setReplicationTopology(
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nlohmann::json::array({{active, replica1}, {active, replica2}})));
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// Still committed
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{
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SCOPED_TRACE("");
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// ************************
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// Test fails because HPS is now 0
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// ************************
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assertNumTrackedAndHPS(0, 1);
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}
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}
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