fix(backup/restore): fixes backup and restore with DROP operations (GRAPHQL-735)

[abhimanyusinghgaur]

Fixes GRAPHQL-735.
See RFC for more details.

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[jarifibrahim]

Got some comments.

[pawanrawal]

Reviewed 15 of 26 files at r1, 6 of 13 files at r2, 15 of 15 files at r3.
Reviewable status: all files reviewed, 13 unresolved discussions (waiting on @abhimanyusinghgaur, @jarifibrahim, @manishrjain, @MichaelJCompton, and @vvbalaji-dgraph)

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edgraph/server.go, line 339 at r3 (raw file):

		}

		// insert a helper record for backup & restore, indicating that drop_all was done

Add a comment that if the server crashes before storing this, that would be an issue.

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protos/pb.proto, line 613 at r3 (raw file):

	}
	DropOp drop_op    = 1;
	string drop_value = 2;

Add a comment that this would only be present when DropOp is ATTR.

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systest/online-restore/online_restore_test.go, line 587 at r3 (raw file):

	// remove backup directories to make sure this test doesn't leave anything behind
	// TODO: This is having some problem on TeamCity
	//cleanupDirs(t, localFsDirs)

Can you create a JIRA ticket to look into it when you come back?

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worker/backup_ee.go, line 173 at r3 (raw file):

	defer cancel()

	resOrErrCh := make(chan interface{}, len(state.Groups))

type backupRes {
res *BackupResponse
err error
}

chan backupRes

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worker/backup_ee.go, line 190 at r3 (raw file):

	var dropOperations []*pb.DropOperation
	for range groups {
		if resOrErr := <-resOrErrCh; resOrErr != nil {

res.err != nil

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worker/backup_processor.go, line 136 at r3 (raw file):

		tl := pr.threads[itr.ThreadId]
		tl.alloc = stream.Allocator(itr.ThreadId)
		kvList, dropOp, err := tl.toBackupList(key, itr)

if err != nil {
return nil, err
}
// append
// return kvList, nil

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worker/backup_processor.go, line 346 at r3 (raw file):

		val, ok := vals[0].Value.([]byte)
		if !ok {
			return nil, errors.Errorf("cannot convert value of dgraph.drop.op to byte array, "+

Also, add the value that is stored.

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x/keys.go, line 560 at r3 (raw file):

	"dgraph.graphql.schema":            {},
	"dgraph.cors":                      {},
	"dgraph.drop.op":                   {},

Add a TODO that we should rename this map.

[abhimanyusinghgaur]

Reviewable status: 30 of 36 files reviewed, 13 unresolved discussions (waiting on @jarifibrahim, @manishrjain, @MichaelJCompton, @pawanrawal, and @vvbalaji-dgraph)

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edgraph/server.go, line 339 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Add a comment that if the server crashes before storing this, that would be an issue.

Done.

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protos/pb.proto, line 613 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Add a comment that this would only be present when DropOp is ATTR.

Done.

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systest/online-restore/online_restore_test.go, line 587 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Can you create a JIRA ticket to look into it when you come back?

Done.

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worker/backup_ee.go, line 173 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

type backupRes {
res *BackupResponse
err error
}

chan backupRes

Done.

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worker/backup_ee.go, line 190 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

res.err != nil

Done.

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worker/backup_processor.go, line 136 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

if err != nil {
return nil, err
}
// append
// return kvList, nil

Done.

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worker/backup_processor.go, line 346 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Also, add the value that is stored.

Done.

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x/keys.go, line 560 at r3 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

Add a TODO that we should rename this map.

Done.