{"record":{"id":"921601f61836dc2e","repo":"dgraph-io/dgraph","slug":"while-fetching-schema","errorCode":null,"errorMessage":"while fetching schema","messagePattern":"while fetching schema","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"query/query.go","lineNumber":3067,"sourceCode":"\t\treturn er, err\n\t}\n\ter.Subgraphs = req.Subgraphs\n\t// calculate metrics.\n\tmetrics := make(map[string]uint64)\n\tfor _, sg := range er.Subgraphs {\n\t\tcalculateMetrics(sg, metrics)\n\t}\n\ter.Metrics = metrics\n\tnamespace, err := x.ExtractNamespace(ctx)\n\tif err != nil {\n\t\treturn er, errors.Wrapf(err, \"While processing query\")\n\t}\n\tschemaProcessingStart := time.Now()\n\tif req.DqlQuery.Schema != nil {\n\t\tpreds := x.NamespaceAttrList(namespace, req.DqlQuery.Schema.Predicates)\n\t\treq.DqlQuery.Schema.Predicates = preds\n\t\tif er.SchemaNode, err = worker.GetSchemaOverNetwork(ctx, req.DqlQuery.Schema); err != nil {\n\t\t\treturn er, errors.Wrapf(err, \"while fetching schema\")\n\t\t}\n\t\ttypeNames := x.NamespaceAttrList(namespace, req.DqlQuery.Schema.Types)\n\t\treq.DqlQuery.Schema.Types = typeNames\n\t\tif er.Types, err = worker.GetTypes(ctx, req.DqlQuery.Schema); err != nil {\n\t\t\treturn er, errors.Wrapf(err, \"while fetching types\")\n\t\t}\n\t}\n\n\tif !x.IsRootNsOperation(ctx) {\n\t\t// Filter the schema nodes for the given namespace.\n\t\ter.SchemaNode = filterSchemaNodeForNamespace(namespace, er.SchemaNode)\n\t\t// Filter the types for the given namespace.\n\t\ter.Types = filterTypesForNamespace(namespace, er.Types)\n\t}\n\treq.Latency.Processing += time.Since(schemaProcessingStart)\n\n\treturn er, nil\n}","sourceCodeStart":3049,"sourceCodeEnd":3085,"githubUrl":"https://github.com/dgraph-io/dgraph/blob/759e242be62c91f8d084da06ad0c8d21256d9c07/query/query.go#L3049-L3085","documentation":"When the request includes a schema clause (schema {} or schema(pred: [...]) DQL), Dgraph fetches schema metadata from the Alpha/Zero cluster over the network via worker.GetSchemaOverNetwork. Failures of that internal RPC surface as this wrapped error. It means schema metadata could not be retrieved, though the main query may have succeeded.","triggerScenarios":"Query string containing a schema{} block while the cluster is unhealthy: unreachable peers, the schema-carrying node down, request timeouts, or the requested predicate not existing and being rejected.","commonSituations":"Cluster during node replacement/rebalance, network partition between Alphas and Zero, misconfigured Zero addresses, or client asking for predicates that were dropped.","solutions":["Check cluster health: curl localhost:8080/health and verify all Alphas and Zero are up","Retry once network issues are resolved; this is often transient during rebalancing","Verify the requested predicates exist in the schema (curl -XPOST localhost:8080/query -d 'schema {}')","Check Dgraph server logs for gRPC timeouts or unreachable peers and fix membership (e.g. remove/re-add dead replicas)"],"exampleFix":"// before: request dropped predicates\nschema(pred: [oldpred]) { type index }\n// after: query existing predicates only\nschema(pred: [name]) { type index }","handlingStrategy":"retry","validationCode":"// Probe cluster health before schema queries\nresp, err := http.Get(\"http://localhost:8080/health\")\nif err != nil || resp.StatusCode != 200 {\n    return errors.New(\"cluster unhealthy; skip schema fetch\")\n}","typeGuard":null,"tryCatchPattern":"er, err := q.ProcessQuery(ctx, req)\nif err != nil && strings.Contains(err.Error(), \"while fetching schema\") {\n    time.Sleep(backoff)\n    er, err = q.ProcessQuery(ctx, req) // retry after transient RPC failure\n}","preventionTips":["Only request predicates you know exist in the schema","Monitor /health and /state for membership issues","Avoid schema queries during rebalancing windows"],"tags":["schema","network","cluster","dgraph"],"backgroundTag":"schema-fetch-failed","analyzedSha":"759e242be62c91f8d084da06ad0c8d21256d9c07","analyzedAt":"2026-09-01T14:42:12.034Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}