[KUDU-2317] Tablet can fail to copy if it has metadata that is too large

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.6.0
• Component/s: tablet copy
• Assignee: Unassigned
• Reporter: William Berkeley
• Created: 20/Feb/18 20:10
• Updated: 26/Feb/18 19:33

Description

The BeginTabletCopySessionResponsePB contains a TabletSuperBlockPB, which contains a listing of all of a tablet's rowsets. If the number of rowsets is so large that the superblock exceeds the rpc max message size (default 50MB), it's not possible to copy the tablet.

The copy client will log messages like

W0214 14:14:51.899601 13430 consensus_peers.cc:396] T 4e3b863d211545aea24a553d48ec3866 P 43f60e1982444bb58405ca3bdfbadcb4 -> Peer 95b8321262394992a03c334039b1fe5e (tserver-00:7050): Unable to begin Tablet Copy on peer: Network error: RPC frame had a length of 52536004, but we only support messages up to 52428800 bytes long.

The copy source will log messages like

W0214 14:14:51.965180 15179 serialization.cc:64] Serialized kudu.tserver.BeginTabletCopySessionResponsePB (58609169 bytes) is larger than the maximum configured RPC message size (52428800 bytes). Sending anyway, but peer may reject the data.

An additional problem this causes is that the connection between the source and client is torn down, which can cause other tablet copies to fail.

Issue Links

• relates to: KUDU-2318 Kudu flushes aggressively even if it can't relieve memory pressure.