Error failed when calling List.rollup

Users Dgraph
1

Hi! I want to upload ~15GB gzipped rdf files To local Dgraph cluster which contain one zero and 3 alpha (all alpha located on same volume, and running in ludicrous mode). Everything run on one AWS instance r5a.24xlarge, 768 GB RAM, 2TB SSD, 96 cores. Dgraph version : v21.03.1

I am using dgraph live loader for this purpose, and I perform upload in several steps. I successfully uploaded ~5 GB of data, but after it I start to see in log of one alpha(s) a lot of error messages like that:

W0901 08:43:08.025933  343110 mvcc.go:148] Error failed when calling List.rollup: while encoding: cannot iterate through the list: cannot initialize iterator when calling List.iterate: cannot read initial list part for list with base key 00000000000000000000066c696e6b6564000000000000694b24: could not read list part with key 04000000000000000000066c696e6b6564000000000000694b240000000000000001: Key not found rolling up key [0 0 0 0 0 0 0 0 0 0 6 108 105 110 107 101 100 0 0 0 0 0 0 105 75 36]

And when I tried to perform some query, I also get similar error:

{
    q(func: type(Bucket)) @filter(eq(period, "hour")) @groupby(timestamp) {
  }
}' | jq
{
  "errors": [
    {
      "message": ": cannot retrieve UIDs from list with key 000000000000000000000b6467726170682e7479706502024275636b6574: cannot initialize iterator when calling List.iterate: cannot read initial list part for list with base key 000000000000000000000b6467726170682e7479706502024275636b6574: could not read list part with key 040000000000000000000b6467726170682e7479706502024275636b65740000000000000001: Key not found",
      "extensions": {
        "code": "ErrorInvalidRequest"
      }
    }
  ],
  "data": null
}

But this query work fine before. I continue to upload data, and when it passed ~13GB, live loader failed with error message:

[23:11:20Z] Elapsed: 05h22m40s Txns: 265151 N-Quads: 265151000 N-Quads/s [last 5s]: 16400 Aborts: 217
panic: rpc error: code = Unknown desc = cannot retrieve predicate information: No connection exists
goroutine 355 [running]:
github.com/dgraph-io/dgraph/dgraph/cmd/live.(*loader).upsertUids(0xc0004a7200, 0xc04269c000, 0x3e8, 0x3e8)
        /ext-go/1/src/github.com/dgraph-io/dgraph/dgraph/cmd/live/run.go:394 +0xeb3
github.com/dgraph-io/dgraph/dgraph/cmd/live.(*loader).processLoadFile.func1(0xc0004ea5a0, 0xc0004a7200, 0xc00078da10)
        /ext-go/1/src/github.com/dgraph-io/dgraph/dgraph/cmd/live/run.go:552 +0x56e
created by github.com/dgraph-io/dgraph/dgraph/cmd/live.(*loader).processLoadFile
        /ext-go/1/src/github.com/dgraph-io/dgraph/dgraph/cmd/live/run.go:487 +0xa5

Any ideas, why suddenly query stop working, and why live loader fail, on such powerful instance, and relative small dataset?

2

What is the timestamp predicate? Group by feature doesn’t work with value edges. Only with relational edges.

3

timestamp is datetime predicate indexed by hour. Actually I was able groupby on this predicate and count nodes, and on other non uid predicates also.

4

Has there been a resolution of this? I’m seeing it now too:
mvcc.go:148] Error failed when calling List.rollup: while encoding:

5

Seeing this as well

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