dotnet/orleans · error · OrleansException

Failed to read table {tableName}: {exc.Message}

Error message

Failed to read table {tableName}: {exc.Message}

What it means

Thrown by the DynamoDB read/scan path when any exception escapes the paged ScanAsync loop while reading a table. The library logs the underlying exception and re-throws it wrapped in a generic OrleansException so callers see a single error type for arbitrary DynamoDB read failures. The inner exception carries the real cause.

Source

Thrown at src/AWS/Shared/Storage/DynamoDBStorage.cs:866

                        }
                    }

                    if (response.LastEvaluatedKey == null || response.LastEvaluatedKey.Count == 0)
                    {
                        break;
                    }
                    else
                    {
                        exclusiveStartKey = response.LastEvaluatedKey;
                    }
                }

                return resultList;
            }
            catch (Exception exc)
            {
                LogWarningFailedToReadTable(_logger, exc, tableName);
                throw new OrleansException($"Failed to read table {tableName}: {exc.Message}", exc);
            }
        }

        /// <summary>
        /// Crete or replace multiple entries in a DynamoDB table (Batch put)
        /// </summary>
        /// <param name="tableName">The name of the table to search for the entry</param>
        /// <param name="toCreate">List of key values for each entry that must be created or replaced in the batch</param>
        /// <returns></returns>
        public Task PutEntriesAsync(string tableName, IReadOnlyCollection<Dictionary<string, AttributeValue>> toCreate)
        {
            LogTracePutEntries(_logger, tableName);

            if (toCreate == null) throw new ArgumentNullException(nameof(toCreate));

            if (toCreate.Count == 0)
                return Task.CompletedTask;

View on GitHub (pinned to fca799fa70)

Solutions

1. Inspect the inner Exception (exc.Message is included in the text) to identify throttling, auth, or ResourceNotFound.
2. If throttling: raise read capacity or switch the table to PAY_PER_REQUEST / on-demand.
3. If the table is missing, recreate it (or re-run Init so the provider recreates it).
4. For transient errors, rely on Orleans' built-in retries or add a caller-side retry policy around the read.

Example fix

// The exception wraps the real cause; surface the inner exception for diagnosis
// before
try { await storage.Read...; } catch (OrleansException e) { log.Error(e.Message); }

// after
try { await storage.Read...(); }
catch (OrleansException e) when (e.InnerException is ProvisionedThroughputExceededException)
{
    // raise capacity or switch to on-demand, then retry
}

// Pre-flight: confirm the table exists and has read capacity headroom before heavy reads
var desc = await DescribeExistingTableAsync(tableName);
if (desc is null) throw new InvalidOperationException($"Table {tableName} does not exist");

static bool IsReadableFailure(Exception inner) => inner switch
{
    ProvisionedThroughputExceededException => true,
    ResourceNotFoundException => true,
    AmazonDynamoDBException => true,
    _ => false
};

try { await storage.ReadAllAsync(...); }
catch (OrleansException ox) when (ox.InnerException is ProvisionedThroughputExceededException)
{
    _logger.LogWarning("DynamoDB read throttled; raising read capacity or retrying");
    throw;
}

When it happens

Trigger: Produced during a paginated consistent-read Scan used by clustering/persistence/reminders lookups when ScanAsync throws. Triggered by DynamoDB throttling (ProvisionedThroughputExceededException), a missing table (ResourceNotFoundException surfaced as inner), network/timeout errors, auth errors, or item-size/expression errors.

Common situations: Read capacity exceeded on a provisioned table; transient network blips to DynamoDB; expired/invalid credentials surfacing during a read; a table that was deleted while the silo was running; malformed filter expressions.

Related errors

• Request rate exceeded, wait {remainingSeconds}s before retry
• Configuration for DynamoDBGrainStorage {name} is invalid. Ta
• Configuration for DynamoDBGrainStorage {name} is invalid. Re
• Configuration for DynamoDBGrainStorage {name} is invalid. Wr
• Data too large to write to DynamoDB table. Size={dataSize} M

AI-assisted analysis of dotnet/orleans@fca799fa70 (2026-08-13). Data as JSON: /api/errors/edf2245a3e95493a. Report an issue: GitHub.