apache/cassandra · error · RuntimeException

You must supply a table name

Error message

You must supply a table name

What it means

parseEntitiesForSnapshot throws RuntimeException('You must supply a table name') when the table portion of a 'keyspace.table' entity string is null. Like the keyspace check, this validates the split tokens before resolving Keyspace and ColumnFamilyStore; an actual nonexistent table is rejected later by getColumnFamilyStore instead.

Solutions

1. Pass the full 'keyspace.table' name with a non-empty table part.
2. Check the table variable in the calling script for emptiness/null before invoking.
3. Use 'keyspace.*' or omit the entity entirely to snapshot all tables in a keyspace rather than a malformed name.

Example fix

// before
String entity = "keyspace1."; // empty table part
// after
String entity = "keyspace1.users";

int dot = entity.indexOf('.');
String table = entity.substring(dot + 1);
if (table.isEmpty()) throw new IllegalArgumentException("Empty table in entity " + entity);

try { takeSnapshot(entities); } catch (RuntimeException e) { if (e.getMessage().equals("You must supply a table name")) throw new IllegalArgumentException("Missing table in entity " + entities, e); throw e; }

When it happens

Trigger: Snapshot entity arguments of the form 'keyspace.' or with a null table token reaching the length==2 branch, e.g. via programmatic/JMX takeSnapshot calls with malformed entity strings.

Common situations: Scripts interpolating an empty/unset table variable into 'ks.$table'; hand-built JMX entity lists; copy-pasted commands dropping the table after the dot.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Cannot take a snapshot on secondary index or invalid column…
• You must supply a keyspace name
• A range supplied to SSTableCursorReader ends before it…
• Argument must have keyspace and table values.
• arguments for -F are json, yaml, table only.

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/194ae88b46ef20e1. Report an issue: GitHub.

Appendix: source

Thrown at src/java/org/apache/cassandra/service/snapshot/TakeSnapshotTask.java:212

    private Set<ColumnFamilyStore> parseEntitiesForSnapshot(String... entities)
    {
        Set<ColumnFamilyStore> entitiesForSnapshot = new HashSet<>();

        if (entities != null && entities.length > 0 && entities[0].contains("."))
        {
            for (String entity : entities)
            {
                String[] splitted = StringUtils.split(entity, '.');
                if (splitted.length == 2)
                {
                    String keyspaceName = splitted[0];
                    String tableName = splitted[1];

                    if (keyspaceName == null)
                        throw new RuntimeException("You must supply a keyspace name");
                    if (tableName == null)
                        throw new RuntimeException("You must supply a table name");

                    Keyspace validKeyspace = Keyspace.getValidKeyspace(keyspaceName);
                    ColumnFamilyStore existingTable = validKeyspace.getColumnFamilyStore(tableName);

                    entitiesForSnapshot.add(existingTable);
                }
                // special case for index which we can not normally create a snapshot for
                // but a snapshot is apparently taken before a secondary index is scrubbed,
                // so we preserve this behavior
                else if (splitted.length == 3)
                {
                    String keyspaceName = splitted[0];
                    String tableName = splitted[1];

                    Keyspace validKeyspace = Keyspace.getValidKeyspace(keyspaceName);
                    ColumnFamilyStore existingTable = validKeyspace.getColumnFamilyStore(tableName);
                    Index indexByName = existingTable.indexManager.getIndexByName(splitted[2]);
                    if (indexByName instanceof CassandraIndex)

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