vitessio/vitess · error

ReloadSchemas: failed to acquire topoReadPool: %w

Error message

ReloadSchemas: failed to acquire topoReadPool: %w

What it means

reloadKeyspaceSchemas (used by Cluster.ReloadSchemas) first acquires topoReadPool to list all keyspaces in one pass. If Acquire fails due to context cancellation or pool exhaustion, the error is wrapped as 'ReloadSchemas: failed to acquire topoReadPool'.

Source

Thrown at go/vt/vtadmin/cluster/cluster.go:2197

		resp.KeyspaceResults, err = c.reloadKeyspaceSchemas(ctx, req)
	}

	if err != nil {
		return nil, err
	}

	return &resp, nil
}

// reloadKeyspaceSchemas reloads schemas in one or more keyspaces in the
// cluster.
func (c *Cluster) reloadKeyspaceSchemas(ctx context.Context, req *vtadminpb.ReloadSchemasRequest) ([]*vtadminpb.ReloadSchemasResponse_KeyspaceResult, error) {
	keyspaces, err := func() (keyspaces []*vtctldatapb.Keyspace, err error) {
		span, ctx := trace.NewSpan(ctx, "Cluster.GetKeyspaces")
		defer span.Finish()

		if err := c.topoReadPool.Acquire(ctx); err != nil {
			return nil, fmt.Errorf("ReloadSchemas: failed to acquire topoReadPool: %w", err)
		}

		// Load all keyspaces up front so we don't have to make one-trip per
		// keyspace to check its existence.
		resp, err := c.Vtctld.GetKeyspaces(ctx, &vtctldatapb.GetKeyspacesRequest{})
		if err != nil {
			return nil, err
		}

		// The request specified no keyspace names, so default to all of them.
		if len(req.Keyspaces) == 0 {
			return resp.Keyspaces, nil
		}

		keyspaceNames := sets.New[string](req.Keyspaces...)

		for _, ks := range resp.Keyspaces {
			if keyspaceNames.Has(ks.Name) {

View on GitHub (pinned to 01a25a7d17)

Solutions

1. Retry ReloadSchemas with a fresh, longer-lived context
2. Reduce concurrent topo read load (stagger schema reload requests)
3. Increase topo_read_pool_size in vtadmin config
4. Check topo backend latency/health

Example fix

// before
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
_, err := c.ReloadSchemas(ctx, req)
// after
ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
_, err := c.ReloadSchemas(ctx, req)

if ctx.Err() != nil {
    return ctx.Err()
}

res, err := c.ReloadSchemas(ctx, req)
if err != nil && strings.Contains(err.Error(), "failed to acquire topoReadPool") {
    // back off and retry with a longer-lived context
}

When it happens

Trigger: Calling ReloadSchemas while topoReadPool is saturated (other topo reads in flight) or the request context is cancelled before the keyspace listing begins.

Common situations: Cluster-wide schema reload triggered while dashboards/other calls are doing topo reads; broad schema reload across many keyspaces combined with slow topo backend; upstream HTTP request deadline already expired.

Related errors

• RefreshState(%v) failed to acquire topoReadPool: %w
• invalid choice for enum
• value must be either a float64 (interpreted as seconds) or a
• flagutil: NewOptionalFlag requires a non-nil parse function
• flagutil: OptionalFlagValue has no parse function; use a con

AI-assisted analysis of vitessio/vitess@01a25a7d17 (2026-09-01). Data as JSON: /api/errors/caa54357883aa9a2. Report an issue: GitHub.