prestodb/presto · error · PrestoException

INDEX_LOADER_TIMEOUT

INDEX_LOADER_TIMEOUT

Error message

Exceeded the time limit of %s loading indexes for index join

What it means

IndexLoader.load builds the index snapshot for an index join by driving a Driver and awaiting each process() future with a timeout. If the index build does not finish within the configured limit, the library throws INDEX_LOADER_TIMEOUT so the query fails fast instead of hanging.

Source

Thrown at presto-main-base/src/main/java/com/facebook/presto/operator/index/IndexLoader.java:355

        }

        public boolean load(List<UpdateRequest> requests)
        {
            // Generate a RecordSet that only presents index keys that have not been cached and are deduped based on lookupSourceInputChannels
            UnloadedIndexKeyRecordSet recordSetForLookupSource = new UnloadedIndexKeyRecordSet(pipelineContext.getSession(), indexSnapshotReference.get(), lookupSourceInputChannels, indexTypes, requests, joinCompiler);

            // Drive index lookup to produce the output (landing in indexSnapshotBuilder)
            try (Driver driver = driverFactory.createDriver(pipelineContext.addDriverContext())) {
                PlanNodeId sourcePlanNodeId = driverFactory.getSourceId().get();
                ScheduledSplit split = new ScheduledSplit(0, sourcePlanNodeId, new Split(INDEX_CONNECTOR_ID, new ConnectorTransactionHandle() {}, new IndexSplit(recordSetForLookupSource)));
                driver.updateSource(new TaskSource(sourcePlanNodeId, ImmutableSet.of(split), true));
                while (!driver.isFinished()) {
                    ListenableFuture<?> process = driver.process();
                    try {
                        process.get(timeout.toMillis(), MILLISECONDS);
                    }
                    catch (TimeoutException e) {
                        throw new PrestoException(INDEX_LOADER_TIMEOUT, format("Exceeded the time limit of %s loading indexes for index join", timeout));
                    }
                    catch (ExecutionException e) {
                        throw new PrestoException(GENERIC_INTERNAL_ERROR, "Error loading index for join", e);
                    }
                    catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                        throw new PrestoException(GENERIC_INTERNAL_ERROR, "Error loading index for join", e);
                    }
                }
            }

            if (indexSnapshotBuilder.isMemoryExceeded()) {
                clearCachedData();
                return false;
            }

            // Generate a RecordSet that presents unique index keys that have not been cached
            UnloadedIndexKeyRecordSet indexKeysRecordSet = (lookupSourceInputChannels.equals(allInputChannels))

View on GitHub (pinned to 55bb57d202)

Solutions

1. Increase the index-loader timeout in the coordinator config (index-loader-timeout)
2. Rewrite the join as a regular hash join (disable index join) so a full build is used
3. Reduce the amount of data going through the index join with better filtering
4. Increase worker resources / parallelism to speed index building

Example fix

// before
query-properties: index-loader-timeout=30s
// after
query-properties: index-loader-timeout=5m (or disable index join for this query)

try { runIndexJoinQuery(sql); } catch (PrestoException e) { if (e.getErrorCode().getName().equals("INDEX_LOADER_TIMEOUT")) { // increase timeout or fall back to hash join
  retryWithHashJoin(sql); } else throw e; }

When it happens

Trigger: Index join where building/loading the lookup index from the probe-side source takes longer than the index-loader timeout (process.get(timeout) raises TimeoutException).

Common situations: Very large build side for the index join; slow underlying connector for index lookups; too-low 'index-loader-timeout' config for the workload.

Related errors

• GENERIC_INTERNAL_ERROR
• QUERY_PLANNING_TIMEOUT
• QUERY_PLANNING_TIMEOUT
• OPTIMIZER_TIMEOUT
• INVALID_TABLE_PROPERTY

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/b3c435f48a173128. Report an issue: GitHub.