vitessio/vitess · error

source shard has no primary: %v

Error message

source shard has no primary: %v

What it means

CreateLookupVindex needs to fetch the source table's schema from a source shard's primary tablet. If the first serving shard's shard record has no PrimaryAlias, there is no primary tablet to query and preparation fails.

Source

Thrown at go/vt/wrangler/materializer.go:656

			continue
		}
		colName := colVindex.Column
		if len(colVindex.Columns) != 0 {
			colName = colVindex.Columns[0]
		}
		if colName == sourceVindexColumns[0] {
			return nil, nil, nil, fmt.Errorf("ColumnVindex for table %v already exists: %v, please remove it and try again", sourceTableName, colName)
		}
	}

	// Validate against source schema
	sourceShards, err := wr.ts.GetServingShards(ctx, keyspace)
	if err != nil {
		return nil, nil, nil, err
	}
	onesource := sourceShards[0]
	if onesource.PrimaryAlias == nil {
		return nil, nil, nil, fmt.Errorf("source shard has no primary: %v", onesource.ShardName())
	}
	req := &tabletmanagerdatapb.GetSchemaRequest{Tables: []string{sourceTableName}}
	tableSchema, err := schematools.GetSchema(ctx, wr.ts, wr.tmc, onesource.PrimaryAlias, req)
	if err != nil {
		return nil, nil, nil, err
	}
	if len(tableSchema.TableDefinitions) != 1 {
		return nil, nil, nil, fmt.Errorf("unexpected number of tables returned from schema: %v", tableSchema.TableDefinitions)
	}

	// Generate "create table" statement
	lines := strings.Split(tableSchema.TableDefinitions[0].Schema, "\n")
	if len(lines) < 3 {
		// Unreachable
		return nil, nil, nil, fmt.Errorf("schema looks incorrect: %s, expecting at least four lines", tableSchema.TableDefinitions[0].Schema)
	}
	var modified []string
	modified = append(modified, strings.Replace(lines[0], sourceTableName, targetTableName, 1))

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Ensure every source shard has a healthy primary (`vtctldclient Placements`/`GetTablets`, run PRS if needed) and retry
2. Wait for any in-flight reshard to finish or use a fully-serving source keyspace
3. Inspect the shard record (`vtctldclient GetShard ks/shard`) and repair missing PrimaryAlias via PlannedReparentShard

Example fix

null

shards, err := ts.GetServingShards(ctx, keyspace)
if err != nil { return err }
for _, sh := range shards {
    if sh.PrimaryAlias == nil {
        return fmt.Errorf("shard %s has no primary; fix replication first", sh.ShardName())
    }
}

func shardHasPrimary(sh *topodata.Shard) bool { return sh.PrimaryAlias != nil }

if err := createLookupVindex(...); err != nil {
    if strings.Contains(err.Error(), "has no primary") {
        return repairShardPrimary(shardName) // run PRS, then retry
    }
    return err
}

When it happens

Trigger: The first serving shard of the source keyspace has no elected primary — e.g. during a reshard while the old shard's primary was removed, after ERS/PRS failure, or a shard record left with PrimaryAlias nil following manual topo edits.

Common situations: Running CreateLookupVindex mid-reshard when a source shard is orphaned; a primary tablet down and not yet promoted; corrupt/legacy topo data lacking primary info.

Related errors

• no primary tablet found
• shard: %s does not have a primary
• tablet %v type change %v -> %v is not an allowed transition
• cannot lookup primary tablet %v for shard %v/%v: %w
• SaveVSchema(%v) = %w

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/3f2acc464efbf5bf. Report an issue: GitHub.