What causes "Failed to retrieve target column for: " in apache/cassandra?

Verify the column name with DESCRIBE TABLE and correct the target

apache/cassandra · error · InvalidRequestException

Failed to retrieve target column for:

Error message

Failed to retrieve target column for:

What it means

After the target string passes shape checks, validateOptions calls TargetParser.parse; if it returns null (no matching column/type combination), SAI throws InvalidRequestException("Failed to retrieve target column for: " + targetColumn). This means the target string is syntactically plausible but does not resolve to an indexable column in the table metadata.

Source

Thrown at src/java/org/apache/cassandra/index/sai/StorageAttachedIndex.java:262

        }

        String targetColumn = options.get(IndexTarget.TARGET_OPTION_NAME);

        if (targetColumn == null)
        {
            throw new InvalidRequestException("Missing target column");
        }

        if (targetColumn.split(",").length > 1)
        {
            throw new InvalidRequestException("A storage-attached index cannot be created over multiple columns: " + targetColumn);
        }

        Pair<ColumnMetadata, IndexTarget.Type> target = TargetParser.parse(metadata, targetColumn);

        if (target == null)
        {
            throw new InvalidRequestException("Failed to retrieve target column for: " + targetColumn);
        }

        // In order to support different index targets on non-frozen map, ie. KEYS, VALUE, ENTRIES, we need to put index
        // name as part of index file name instead of column name. We only need to check that the target is different
        // between indexes. This will only allow indexes in the same column with a different IndexTarget.Type.
        //
        // Note that: "metadata.indexes" already includes current index
        if (metadata.indexes.stream().filter(index -> index.getIndexClassName().equals(StorageAttachedIndex.class.getName()))
                            .map(index -> TargetParser.parse(metadata, index.options.get(IndexTarget.TARGET_OPTION_NAME)))
                            .filter(Objects::nonNull).filter(t -> t.equals(target)).count() > 1)
        {
            throw new InvalidRequestException("Cannot create more than one storage-attached index on the same column: " + target.left);
        }

        Map<String, String> analysisOptions = AbstractAnalyzer.getAnalyzerOptions(options);
        if (target.left.isPrimaryKeyColumn() && !analysisOptions.isEmpty())
        {
            throw new InvalidRequestException(ANALYSIS_ON_KEY_COLUMNS_MESSAGE + new CqlBuilder().append(analysisOptions));

View on GitHub (pinned to 88fd0f6a0e)

Solutions

Verify the column name with DESCRIBE TABLE and correct the target
Remove unsupported wrappers — use plain column name for scalars, keys/values/entries only for maps, full() only for frozen collections
Quote the identifier if the column has mixed case
Recreate the index after the column exists

Example fix

// before
CREATE CUSTOM INDEX idx ON ks.tbl (Email) USING 'StorageAttachedIndex'; // no such column
// after
CREATE CUSTOM INDEX idx ON ks.tbl (email) USING 'StorageAttachedIndex';

Defensive patterns

Strategy: validation

Validate before calling

if (metadata.getColumn(new ColumnIdentifier(targetColumn, true)) == null && TargetParser.tryParse(metadata, targetColumn) == null)
    throw new IllegalArgumentException("Target does not resolve to an indexable column: " + targetColumn);

Try / catch

try { session.execute(ddl); } catch (InvalidRequestException e) { if (e.getMessage().contains("Failed to retrieve target column")) { /* correct column name or wrapper */ } else throw e; }

Prevention

Confirm column names via DESCRIBE TABLE before creating indexes (watch identifier case)
Only use keys/values/entries on maps and full() on frozen collections
Run CREATE INDEX statements through a staging environment first

When it happens

Trigger: CREATE CUSTOM INDEX USING StorageAttachedIndex with a target naming a nonexistent column, an unsupported function wrapper (e.g. keys() on a non-map), or invalid syntax like full() on non-frozen types.

Common situations: Typos in column names; using keys()/values()/entries() on set/list columns or plain columns; target on a column dropped before index creation; case-sensitivity mistakes (unquoted "Email" vs email).

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

AI-assisted analysis of apache/cassandra@88fd0f6a0e (2026-09-10). Data as JSON: /api/errors/f447761b68ef6cbf. Report an issue: GitHub.