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  • KIP-216: IQ should throw different exceptions for different errors

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(Working in Progress)

 

 

Table of Contents

Status

Current stateUnder Discussion

...

Motivation

Currently, IQ throws InvalidStateStoreException for any types of error, that means a user cannot handle different types of error.

Because of that, we should throw different exceptions for each type.

Proposed Changes

There are add four new exceptions:

Code Block
languagejava
public class StateStoreMigratedException extends InvalidStateStoreException
public class StateStoreRetryableException extends InvalidStateStoreException
public class StateStoreFailException extends InvalidStateStoreException
public class StateStoreClosedException extends InvalidStateStoreException

Three categories exception throw to user

  • StateStoreRetriableException: The application instance in the state of rebalancing, the user just need retry and wait until rebalance finished.
  • StateStoreMigratedException: The store got migrated and not hosted in application instance, the users need to rediscover the store.

  • StateStoreFailException: Fatal error when access state store, the user cannot retry or rediscover.

One internal exception: StateStoreClosedException.

The following is the public method that users will call:

  • KafkaStreams
    • stores()
  • ReadOnlyKeyValueStore(CompositeReadOnlyKeyValueStore)
    • get(k)
    • range(from, to)
    • all()
    • approximateNumEntries()
  • ReadOnlySessionStore(CompositeReadOnlySessionStore)
    • fetch(k)
    • fetch(from, to)
  • ReadOnlyWindowStore(CompositeReadOnlyWindowStore)
    • fetch(k, rf, tt)
    • fetch(from, to, rf, tt)
    • all()
    • fetchAll()
  • KeyValueIterator(DelegatingPeekingKeyValueIterator)
    • next()
    • hasNext()
    • peekNextKey()
  • WindowStoreIterator(MeteredWindowStoreIterator)
    • next()
    • hasNext()
    • peekNextKey()

To distinguish different types of error, we need to handle all InvalidStateStoreExceptions better during these public methods invoked. The main change is to introduce new exceptions that extend from InvalidStateStoreException. InvalidStateStoreException is not thrown at all anymore, but only new sub-classes.

Code Block
languagejava
public# classTwo KafkaStreamscategory {exceptions
    public <T>class TRetryableStateStoreException store(finalextends String storeName, final QueryableStoreType<T> queryableStoreType);
}
 
InvalidStateStoreException
public class CompositeReadOnlyKeyValueStore<K,FatalStateStoreException V>extends implementsInvalidStateStoreException
ReadOnlyKeyValueStore<K,
V>
{# Retryable exceptions
  public V get(final K key);
    public KeyValueIterator<K, V> range(final K from, final K to);
    public KeyValueIterator<K, V> all();
    public long approximateNumEntries();
}
 
public class CompositeReadOnlySessionStore<K, V> implements ReadOnlySessionStore<K, V> {
    public KeyValueIterator<Windowed<K>, V> fetch(final K key);
    public KeyValueIterator<Windowed<K>, V> fetch(final K from, final K to);
}
 
public class CompositeReadOnlyWindowStore<K, V> implements ReadOnlyWindowStore<K, V> {
    public WindowStoreIterator<V> fetch(final K key, final long timeFrom, final long timeTo);
    public KeyValueIterator<Windowed<K>, V> fetch(final K from, final K to, final long timeFrom, final long timeTo);
    public KeyValueIterator<Windowed<K>, V> all();
    public KeyValueIterator<Windowed<K>, V> fetchAll(final long timeFrom, final long timeTo);
}
 
class DelegatingPeekingKeyValueIterator<K, V> implements KeyValueIterator<K, V>, PeekingKeyValueIterator<K, V> {
    public synchronized boolean hasNext();
    public synchronized KeyValue<K, V> next();
    public KeyValue<K, V> peekNext();
}

class MeteredWindowStoreIterator<V> implements WindowStoreIterator<V> {
    public boolean hasNext();
    public KeyValue<Long, V> next();
    public Long peekNextKey()
}

During user call one of above methods, we should check KafkaStreams state by the following rule when InvalidStateStoreException is thrown:

  • If state is RUNNING or REBALANCING:
    • StateStoreClosedException: should be wrapped to StateStoreRetriableException
    • StateStoreMigratedException: should not be wrapped, directly thrown
  • if state is PENDING_SHUTDOW or ERROR or NOT_RUNNING:
    • wrap InvalidStateStoreException to StateStoreFailException

Call Trace

 

Expand
titleCall trace 1: KafkaStreams#store()
  • KafkaStreams#store() (v)
    • QueryableStoreProvider#getStore() (v)
      • GlobalStateStoreProvider#stores() (v)
      • StreamThreadStateStroeProvider#stores() (v)
Expand
titleCall trace 2: ReadOnlyKeyValueStore#get()
  • CompositeReadOnlyKeyValueStore#get() (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • MeteredKeyValueBytesStore#get()
      • InnerMeteredKeyValueStore#get()
        • CachingKeyValueStore#get()
          • AbstractStateStore#validateStoreOpen() (v)
            • RocksDBStore#isOpen()
        • CachingKeyValueStore#getInternal()
          • ChangeLoggingKeyValueBytesStore#get()
            • RocksDBStore#get()
              • RocksDBStore#validateStoreOpen() (v)
            • RocksDBStore#getInternal()
Expand
titleCall trace 3: ReadOnlyKeyValueStore#range()
  • CompositeReadOnlyKeyValueStore#range() (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • return new DelegatingPeekingKeyValueIterator<>()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositKeyValueIterator#hasNext()
      • NextIteratorFunction#apply() (v)
        • MeteredKeyValueBytesStore#range()
          • InnerMeteredKeyValueStore#range()
            • CachingKeyValueStore#range()
              • AbstractStateStore#validateStoreOpen() (v)
              • ChangeLoggingKeyValueBytesStore#range()
                • RocksDBStore#range()
                  • RocksDBStore#validateStoreOpen() (v)
                  • return new RocksDBRangeIterator()
              • return new MergedSortedCacheKeyValueBytesStoreIterator()
            • return new MeteredKeyValueIterator()
          • return
        • return
      • return
    • CompositKeyValueIterator#next()
      • MeteredKeyValueIterator#next()
        • MergedSortedCacheKeyValueBytesStoreIterator#next()
          AbstractMergedSortedCacheStoreIterator#next()
          • RocksDBRangeIterator#hasNext()
            RocksDBIterator#hasNext() (v)
              • RocksIterator#isValid()
          • AbstractMergedStortedCacheStoreIterator#nextSrtoreValue()
            • RocksDBRangeIterator#next()
              RocksDBIterator#next()
              • RocksDbIterator#hasNext() (v)
              • RocksDbIterator#getKeyValue()
              • RocksIterator#next()
              • return keyvalue entry
            • return
          • return
        • return outerkeyvalue
      • return
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • return keyvalue
Expand
titleCall trace 4: ReadOnlyKeyValueStore#all()
  • CompositeReadOnlyKeyValueStore#all() (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • return new DelegatingPeekingKeyValueIterator<>()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositKeyValueIterator#hasNext()
      • NextIteratorFunction#apply() (v)
        • MeteredKeyValueBytesStore#all()
          • InnerMeteredKeyValueStore#all()
            CachingKeyValueStore#all()
            • AbstractStateStore#validateStoreOpen() (v)
              • ChangeLoggingKeyValueBytesStore#all()
                • RocksDBStore#all()
                  • RocksDBStore#validateStoreOpen() (v)
                  • return new RocksDBIterator()
                • return
              • return new MergedSortedCacheKeyValueBytesStoreIterator()
            • return new MeteredKeyValueIterator()
          • return
        • return
      • return
    • CompositKeyValueIterator#next()
      • MeteredKeyValueIterator#next()
        • MergedSortedCacheKeyValueBytesStoreIterator#next()
          AbstractMergedSortedCacheStoreIterator#next()
          • MemoryLRUCacheBytesIterator.hasNext()
          • DelegatingPeekingKeyValueIterator.hasNext() (v)
          • AbstractMergedSortedCacheStoreIterator#nextStoreValue()
            • DelegatingPeekingKeyValueIterator#next()
              • DelegatingPeekingKeyValueIterator#hasNext() (v)
            • return
          • return
        • return outerkeyvalue
      • return
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • return keyvalue

 

Expand
titleCall trace 5: ReadOnlyKeyValueStore#approximateNumEntries()
  • CompositeReadOnlyKeyValueStore#approximateNumEntries() (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • MeteredKeyValueBytesStore#approximateNumEntries()
      • InnerMeteredKeyValueStore#approximateNumEntries()
        • CachingKeyValueStore#approximateNumEntries()
          • AbstractStateStore#validateStoreOpen() (v)
            • RocksDBStore#isOpen()
          • RocksDBStore#approximateNumEntries()
            • RocksDBStore#validateStoreOpen() (v)
            • return value
          • return
        • return
      • return
    • return total

...

titleCall trace 6: ReadOnlySessionStore#fetch(key)
  • CompositeReadOnlySessionStore#fetch(key) (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • MeteredSessionStore#fetch(key)
      • MeteredSessionStore#findSessions()
        • CachingSessionStore#findSessions()
          • AbstractStateStore#validateStoreOpen() (v)
          • ChangeLoggingSessionBytesStore#findSessions()
            • RocksDBSessionStore.findSessions(k)
              • RocksDBSessionStore.findSessions(from, to)
                • RocksDBSegmentedBytesStore#fetch()
                  • SessionKeySchema#segmentsToSearch()
                    • Segments#segments() (v)
                      • Segments#getSegment()
                        • ConcurrentHashMap#get()
                        • Segments#isSegment()
                        • return segment
                      • retiurn segments
                    • return
                  • return new SegmentIterator()
                • return new WrappedSessionStoreIterator()
              • return
            • return
          • return new MergedSortedCacheSessionStoreIterator()
        • return new MeteredWindowedKeyValueIterator()
      • return
    • MeteredWindowedKeyValueIterator#hasNext()
      • MergedSortedCacheSessionStoreIterator#hasNext()
        AbstraceMergedSortedCacheStoreIterator#hasNext()
        • FilteredCacheIterator#hasNext()
        • WrappedSessionStoreIterator#hasNext()
          • SegmentIterator#hasNext()
            • Segment.range(from, to)
              RocksDBStore.range(from, to)
              • RocksDBStore.validateStoreOpen() (v)
              • return new RocksDBRangeIterator()
            • return
          • return
        • return
      • return iterator(MeteredWindowedKeyValueIterator)
  • MeteredWindowedKeyValueIterator#next()
    • MergedSortedCacheSessionStoreIterator#next()
      AbstractMergedSortedCacheStoreIterator#next()
      • AbstractMergedSortedCacheStoreIterator#hasNext()
      • FilteredCacheIterator#hasNext()
      • WrappedSessionStoreIterator#hasNext()
        • SegmentIterator#hasNext()
          • Segment.range(from, to)
            RocksDBStore.range(from, to)
            • RocksDBStore.validateStoreOpen() (v)
            • return new RocksDBRangeIterator()
          • return
        • return
      • MergedSortedCacheSessionStoreIterator#nextStoreValue()
        AbstractMergedSortedCacheStoreIterator#nextStoreValue()
        • WrappedSessionStoreIterator#next()
          • SegmentIterator#next()
            • RocksDBRangeIterator#next()
              RocksDbIterator#next()
              • RocksDbIterator#getKeyValue()
              • RocksIterator#next()
              • return entry
            • return
          • return
        • return
      • return
    • return

...

Expand
titleCall trace 7: ReadOnlySessionStore#fetch(from, to)
  • CompositeReadOnlySessionStore#fetch(from, to) (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • return new DelegatingPeekingKeyValueIterator<>()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositKeyValueIterator#hasNext()
      • NextIteratorFunction#apply(store)
        • MeteredSessionStore#fetch(from, to)
          • MeteredSessionStore#findSession(from, to, 0, t)
            • CachingSessionStore#findSession(from, to, 0, t)
              • CachingSessionStore#validStoreOpen()
                AbstractStateStore#validStoreOpen() (v)
                • ChangeLoggingSessionBytesStore#isOpen()
                  • RocksDBSessionStore#isOpen()
                    AbstractStateStore#isOpen()
                    • RocksDBSegmentedBytesStore#isOpen()
                    • return
                  • return
                • return
              • ChangeLoggingSessionBytesStore#findSesisons()
                • RocksDBSessionStore#findSessions()
                  • RocksDBSegmentedBytesStore#fetch()
                    • SessionKeySchema#segmentsToSearch()
                      • Segments#segments() (v)
                        • RocksDBStore#isOpen()
                      • return new SegmentIterator()
                    • return new WrappedSessionStoreIterator()
                  • return
                • return
              • return new MergedSortedCacheSessionStoreIterator()
            • return MeteredWindowedKeyValueIterator()
          • return
        • return
      • MeteredWindowedKeyValueIterator#hasNext()
        • MergedSortedCacheSessionStoreIterator#hasNext()
          AbstractMergedSortedCacheStoreIterator#hasNext()
          • FilteredCacheIterator#hasNext()
          • WrappedSessionStoreIterator#hasNext()
            • SegmentIterator#hasNext()
              • Segment.range(from, to)
                RocksDBStore.range(from, to)
                • RocksDBStore.validateStoreOpen() (v)
                • return new RocksDBRangeIterator()
              • return
            • return
          • return
        • return
      • return
    • CompositeKeyValueIterator#next()
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • return keyvalue
Expand
titleCall trace 8: ReadOnlyWindowStore#fetch(key)
  • CompositeReadOnlySessionStore#fetch(key) (v)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
    • MeteredWindowStore#fetch()
      • CachingWindowStore#fetch(k, tf, tt)
        • AbstractStateStore#validateStoreOpen()
          • ChangeLoggingWindowBytesStore#isOpen()
            • AbstractStateStore#isOpen()
              • RocksDBWindowBytesStore#isOpen()
                • RocksDBSegmentedBytesStore#isOpen()
                • return
              • return
            • return
          • return
        • ChangeLoggingWindowBytesStore#fetch()
          • RocksDBWindowStoreBytesStore#fetch()
            • RocksDBSegmentedBytesStore#fetch()
              • WindowKeySchema#segmentsToSearch()
                • Segments#segments()
                  • RocksDBStore#isOpen()
                  • return segments
                • return
              • return new SegmentIterator()
            • WindowStoreIteratorWrapper.bytesIterator()
              • return new WrappedWindowStoreBytesIterator()
            • return
          • return
        • ThreadCache#range()
          • return new MemoryLRUCacheBytesIterator
        • return new MergedSortedCacheWindowStoreIterator
      • return new MeteredWindowStoreIterator
    • MeteredWindowStoreIterator#hasNext()
      AbstractMergedSortedCacheStoreIterator#hasNext()
      • WrappedWindowStoreIterator#hasNext()
        • SegmentIterator#hasNext()
          • Segment#range()
            RocksDBStore#range()
            • RocksDBStore#validateStoreOpen()
            • return RocksDBRangeIterator
          • return
        • return
      • return
    • return
  • MeteredWindowStoreIterator#hasNext()
    • MeteredSortedCacheWindowStoreIterator#hasNext()
      AbstractMergedSortedCacheStoreIterator#hasNext()
      • WrappedWindowStoreIterator#hasNext()
        • SegmentIterator#hasNext()
          • Segment#range()
            RocksDBStore#range()
            • RocksDBStore#validateStoreOpen() (v)
            • return RocksDBRangeIterator
          • return
        • return
      • return
    • return
  • MeteredWindowStoreIterator#next()
    • MergedSortedCacheWindowStoreIterator#next()
      AbstractMergedSortedCacheStoreIterator#next()
      • WrappedWindowStoreBytesIterator#hasNext()
        • SegmentIterator#hasNext()
          • return
        • return
      • AbstractMergedSortedCacheStoreIterator#nextStoreValue()
        • WrappedWindowStoreBytesIterator#next()
          • SegmentIterator#next()
            • SegmentIterator#hasNext()
              • return
            • RocksDBRangeIterator#next()
              • RocksDBRangeIterator#hasNext()
                • RocksDBIterator#hasNext() (v)
                • return
              • RocksIterator#next()
              • return entry
            • return
          • return keyvalue
        • return
      • return
    • return keyvalue
Expand
titleCall trace 9: ReadOnlyWindowStore#fetch(from, to)
  • CompositeReadOnlyWindowStore#fetch(from, to)
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
      • return
    • return new DelegatingPeekingKeyValueIterator()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositeKeyValueIterator#hasNext()
      • NextIteratorFunciton#apply()
        • MeteredWindowStore#fetch()
          • CachingWindowStore#fetch()
            • AbstractStateStore#validateStoreOpen() (v)
            • ChangeLoggingWindowBytesStore#fetch()
              • RocksDBWindowBytesStore#fetch()
                • RocksDBSegmentedBytesStore#fetch()
                  • WindowKeySchema#segmentsToSearch()
                    • Segments#segments() (v)
                      • return
                    • return
                  • return SegmentIterator
                • return keyvalueIterator
              • return
            • ThreadCache.range()
              • return new MemoryLRUCacheBytesIterator
            • WindowKeySchema#hasNextCondition()
            • return new MergedSortedCacheWindowStoreKeyValueIterator()
          • return MeteredWindowKeyValueIterator()
        • return
      • MeteredWindowedKeyValueIterator#hasNext()
        • MergedSortedCacheWindowStoreKeyValueIterator#hasNext()
          AbstractMergedSortedCacheStoreIterator
          • WrappedWindowStoreBytesIterator#hasNext()
            WrappedKeyValueIterator#hasNext()
            • SegementIterator#hasNext()
              • Segment#range()
                RocksDBStore#range()
                • RocksDBStore#validateStoreOpen() (v)
                • return RocksDBRangeIterator
              • return
          • return
        • return
      • return
    • CompositeKeyValueIterator#next()
      • MeteredWindowedKeyValueIterator#next()
        • MergedSortedCacheWindowStoreKeyValueIterator#next()
          AbstractMergedSortedCacheStoreIterator#next()
          • AbstractMergedSortedCacheStoreIterator#hasNext()
          • AbstractMergedSortedCacheStoreIterator#nextStoreValue()
            • WrappedWindowStoreBytesIterator#next()
              • SegmentIteator#hasNext()
              • SegmentIterator#next()
                • SegmentIterator#hasNext() (v)
                • RocksDBRangeIterator#next()
                  RocksDbIterator#next()
                  • RocksDbIterator#hasNext()
                  • RocksIterator#next()
                  • return entry
                • return
              • return keyvalue
            • return
          • return keyvalue
        • return
      • return
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • DelegatingPeekingKeyValueIterator#hasNext()
    • return
Expand
titleCall trace 10: ReadOnlyWindowStore#all()
  • CompositeReadOnlyWindowStore#all()
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
      • return
    • return new DelegatingPeekingKeyValueIterator()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositeKeyValueIterator#hasNext()
      • NextIteratorFunciton#apply()
        • MeteredWindowStore#all()
          • CachingWindowStore#all()
            • AbstractStateStore#validateStoreOpen() (v)
            • ChangeLoggingWindowBytesStore#all()
              • RocksDBWindowBytesStore#all()
                • RocksDBSegmentedBytesStore#all()
                  • Segments#allSegments() (v)
                  • return new SegmentIterator()
                • return keyValueIterator
              • return
            • ThreadCache#all()
              • return new MemoryLRUCacheBytesIterator
            • return new MergedSortedCacheWindowStoreKeyValueIterator
          • return new MeteredWindowedKeyValueIterator()
        • return
      • MeteredWindowedKeyValueIterator#hasNext()
        • MergedSortedCacheWindowStoreKeyValueIterator#hasNext()
          AbstractMergedSortedCacheStoreIterator#hasNext()
          • WrappedKeyValueIterator#hasNext()
            • SegmentIterator#hasNext() (v)
              • return currentIterator
            • return
          • return
        • return
      • return
    • CompositeKeyValueIterator#next()
      • MeteredWindowedKeyValueIterator#next()
        • MergedSortedCacheWindowStoreKeyValueIterator#next()
          AbstractMergedSortedCacheStoreIterator#next()
          • WrappedKeyValueIterator#hasNext()
            • SegmentIterator#hasNext()
          • AbstractMergedSortedCacheStoreIterator#nextStoreValue()
            • WrappedKeyValueIterator#next()
              • SegmentIterator#next()
                • RocksDbIterator#next()
                  • RocksDbIterator#hasNext() (v)
                  • RocksIterator.next()
                  • return entry
                • return
              • return keyvalue
            • return
          • return
        • return keyvalue
      • return
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • DelegatingPeekingKeyValueIterator#hasNext()
    • return
Expand
titleCall trace 11: ReadOnlyWindowStore#fetchAll()
  • CompositeReadOnlyWindowStore#fetchAll()
    • WrappingStoreProvider#stores() (v)
      • StreamThreadStateStoreProvider#stores() (v)
      • return
    • return new DelegatingPeekingKeyValueIterator()
  • DelegatingPeekingKeyValueIterator#hasNext() (v)
    • CompositeKeyValueIterator#hasNext()
      • NextIteratorFunciton#apply()
        • MeteredWindowStore#fetchAll()
          • CachingWindowStore#fetchAll()
            • AbstractStateStore#validateStoreOpen() (v)
            • ChangeLoggingWindowBytesStore#fetchAll()
              • RocksDBWindowBytesStore#fetchAll()
                • RocksDBSegmentedBytesStore#fetchAll()
                  • Segments#allSegments() (v)
                  • return new SegmentIterator()
                • return keyValueIterator
              • return
            • ThreadCache#all()
              • return new MemoryLRUCacheBytesIterator
            • return new MergedSortedCacheWindowStoreKeyValueIterator
          • return new MeteredWindowedKeyValueIterator()
        • return
      • MeteredWindowedKeyValueIterator#hasNext()
        • MergedSortedCacheWindowStoreKeyValueIterator#hasNext()
          AbstractMergedSortedCacheStoreIterator#hasNext()
          • WrappedKeyValueIterator#hasNext()
            • SegmentIterator#hasNext() (v)
              • return currentIterator
            • return
          • return
        • return
      • return
    • CompositeKeyValueIterator#next()
      • MeteredWindowedKeyValueIterator#next()
        • MergedSortedCacheWindowStoreKeyValueIterator#next()
          AbstractMergedSortedCacheStoreIterator#next()
          • WrappedKeyValueIterator#hasNext()
            • SegmentIterator#hasNext() (v)
            • return
          • AbstractMergedSortedCacheStoreIterator#nextStoreValue()
            • WrappedKeyValueIterator#next()
              • SegmentIterator#next()
                • RocksDbIterator#next()
                  • RocksDbIterator#hasNext() (v)
                  • RocksIterator.next()
                  • return entry
                • return
              • return keyvalue
            • return
          • return
        • return keyvalue
      • return
    • return
  • DelegatingPeekingKeyValueIterator#next()
    • DelegatingPeekingKeyValueIterator#hasNext()
    • return

...

 

Code Block
languagejava
public interface QueryableStoreType<T> {
    // TODO: pass stream instance parameter
    T create(final KafkaStreams streams, final StateStoreProvider storeProvider, final String storeName);
}
Code Block
languagejava
titleclass QueryableStoreProvider
public <T> T getStore(final String storeName, final QueryableStoreType<T> queryableStoreType) {
    final List<T> globalStore = globalStoreProvider.stores(storeName, queryableStoreType);
    if (!globalStore.isEmpty()) {
        return queryableStoreType.create(new WrappingStoreProvider(Collections.<StateStoreProvider>singletonList(globalStoreProvider)), storeName);
    }
    final List<T> allStores = new ArrayList<>();
    for (StateStoreProvider storeProvider : storeProviders) {
        allStores.addAll(storeProvider.stores(storeName, queryableStoreType));
    }
    if (allStores.isEmpty()) {
        // TODO: Replace with StateStoreMigratedException
        throw new InvalidStateStoreException("the state store, " + storeName + ", may have migrated to another instance.");
    }
    return queryableStoreType.create(
            new WrappingStoreProvider(storeProviders),
            storeName);
}
Code Block
languagejava
titleclass GlobalStateStoreProvider
public <T> List<T> stores(final String storeName, final QueryableStoreType<T> queryableStoreType) {
    final StateStore store = globalStateStores.get(storeName);
    if (store == null || !queryableStoreType.accepts(store)) {
        return Collections.emptyList();
    }
    if (!store.isOpen()) {
        // TODO: Replace with StateStoreClosedException
        throw new InvalidStateStoreException("the state store, " + storeName + ", is not open.");
    }
    return (List<T>) Collections.singletonList(store);
}
Code Block
languagejava
titleclass StreamThreadStateStoreProvider
 public <T> List<T> stores(final String storeName, final QueryableStoreType<T> queryableStoreType) {
    if (streamThread.state() == StreamThread.State.DEAD) {
        return Collections.emptyList();
    }
    if (!streamThread.isRunningAndNotRebalancing()) {
        // TODO: Replace with StateStoreMigratedException
        throw new InvalidStateStoreException("Cannot get state store " + storeName + " because the stream thread is " +
                streamThread.state() + ", not RUNNING");
    }
    final List<T> stores = new ArrayList<>();
    for (Task streamTask : streamThread.tasks().values()) {
        final StateStore store = streamTask.getStore(storeName);
        if (store != null && queryableStoreType.accepts(store)) {
            if (!store.isOpen()) {
                // TODO: Replace with StateStoreClosedException
                throw new InvalidStateStoreException("Cannot get state store " + storeName + " for task " + streamTask +
                        " because the store is not open. The state store may have migrated to another instances.");
            }
            stores.add((T) store);
        }
    }
    return stores;
}
Code Block
languagejava
titleclass WrappingStoreProvider
public <T> List<T> stores(final String storeName, QueryableStoreType<T> type) {
    final List<T> allStores = new ArrayList<>();
    for (StateStoreProvider provider : storeProviders) {
        final List<T> stores =
            provider.stores(storeName, type);
        allStores.addAll(stores);
    }
    if (allStores.isEmpty()) {
        // Replace with StateStoreMigratedException
        throw new InvalidStateStoreException("the state store, " + storeName + ", may have migrated to another instance.");
    }
    return allStores;
}
Code Block
languagejava
titleclass AbstractStateStore
void validateStoreOpen() {
    if (!innerState.isOpen()) {
        // TODO: Replace with StateStoreClosedException
        throw new InvalidStateStoreException("Store " + innerState.name() + " is currently closed.");
    }
}
Code Block
languagejava
titleclass RocksDBStore
private void validateStoreOpen() {
    if (!open) {
        // TODO: Replace with StateStoreClosedException
        throw new InvalidStateStoreException("Store " + this.name + " is currently closed");
    }
}
Code Block
languagejava
titleclass RocksDBIterator
public synchronized boolean hasNext() {
    if (!open) {
        // TODO: Replace with StateStoreClosedException
        throw new InvalidStateStoreException(String.format("RocksDB store %s has closed", storeName));
    }

    return iter.isValid();
}
Code Block
languagejava
titleclass DelegatingPeekingKeyValueIterator
public synchronized boolean hasNext() {
    if (!open) {
        // TODO: Replace with StateStoreClosedException
        throw new InvalidStateStoreException(String.format("Store %s has closed", storeName));
    }
    if (next != null) {
        return true;
    }

    if (!underlying.hasNext()) {
        return false;
    }

    next = underlying.next();
    return true;
}
Code Block
languagejava
titleclass Segments
List<Segment> segments(final long timeFrom, final long timeTo) {
    final long segFrom = Math.max(minSegmentId, segmentId(Math.max(0L, timeFrom)));
    final long segTo = Math.min(maxSegmentId, segmentId(Math.min(maxSegmentId * segmentInterval, Math.max(0, timeTo))));

    final List<Segment> segments = new ArrayList<>();
    for (long segmentId = segFrom; segmentId <= segTo; segmentId++) {
        Segment segment = getSegment(segmentId);
        if (segment != null && segment.isOpen()) {
            try {
                segments.add(segment);
            } catch (InvalidStateStoreException ise) {  // TODO: Replace with StateStoreClosedException
                // segment may have been closed by streams thread;
            }
        }
    }
    return segments;
}

List<Segment> allSegments() {
    final List<Segment> segments = new ArrayList<>();
    for (Segment segment : this.segments.values()) {
        if (segment.isOpen()) {
            try {
                segments.add(segment);
            } catch (InvalidStateStoreException ise) {  // TODO: Replace with StateStoreClosedException
                // segment may have been closed by streams thread;
            }
        }
    }
    Collections.sort(segments);
    return segments;
}
Code Block
languagejava
titleclass SegmentIterator
public boolean hasNext() {
    boolean hasNext = false;
    while ((currentIterator == null || !(hasNext = hasNextCondition.hasNext(currentIterator)) || !currentSegment.isOpen())
            && segments.hasNext()) {
        close();
        currentSegment = segments.next();
        try {
            if (from == null || to == null) {
                currentIterator = currentSegment.all();
            } else {
                currentIterator = currentSegment.range(from, to);
            }
        } catch (InvalidStateStoreException e) {  // TODO: Replace with StateStoreClosedException
            // segment may have been closed so we ignore it.
        }
    }
    return currentIterator != null && hasNext;
}

 

 

 

class StreamThreadNotStartedException extends RetryableStateStoreException
public class StreamThreadRebalancingException extends RetryableStateStoreException
public class StateStoreMigratedException extends RetryableStateStoreException


# Fatal exceptions
public class StreamThreadNotRunningException extends FatalStateStoreException

Various state store exceptions can classify into two category exceptions: RetryableStateStoreException and FatalStateStoreException. The user can use the two exceptions if they only need to distinguish whether it can retry.

  • Retryable exceptions
    • StreamThreadNotStartedException: will be thrown when streams thread state is CREATED, the user can retry until to RUNNING.
    • StreamThreadRebalancingException: will be thrown when stream thread is not running and stream state is REBALANCING, the user just retry and wait until rebalance finished (RUNNING).
    • StateStoreMigratedException: will be thrown when state store already closed and stream state is REBALANCING.
  • Fatal exceptions
    • KafkaStreamsNotRunningException: will be thrown when stream thread is not running and stream state is PENDING_SHUTDOWN / NOT_RUNNING / ERROR. The user cannot retry when this exception is thrown.
    • StateStoreNotAvailableException: will be thrown when state store closed and stream thread is PENDING_SHUTDOWN / NOT_RUNNING / ERROR. The user cannot retry when this exception is thrown.
    • UnknownStateStoreException: will be thrown when passing an unknown state store.


The following is the public methods that users will call to get state store instance:

  • KafkaStreams
    • store(storeName, queryableStoreType)
Info
Throw exceptions: StreamThreadNotStartedException, StreamThreadRebalancingException, KafkaStreamsNotRunningExceptionUnknownStateStoreException


The following is the public methods that users will call to get store values:

  • interface ReadOnlyKeyValueStore(class CompositeReadOnlyKeyValueStore)
    • get(key)
    • range(from, to)
    • all()
    • approximateNumEntries()
  • interface ReadOnlySessionStore(class CompositeReadOnlySessionStore)
    • fetch(key)
    • fetch(from, to)
  • interface ReadOnlyWindowStore(class CompositeReadOnlyWindowStore)
    • fetch(key, time)
    • fetch(key, from, to)

    • fetch(from, to, fromTime, toTime)
    • all()
    • fetchAll(from, to)
    • @Deprecated fetch(key, timeFrom, timeTo)
    • @Deprecated fetch(from, to, timeFrom, timeTo)
    • @Deprecated fetchAll(timeFrom, timeTo)
  • interface KeyValueIterator(class DelegatingPeekingKeyValueIterator)
    • next()
    • hasNext()
    • peekNextKey()
Info

All the above methods could be throw following exceptions: 

StreamThreadRebalancingExceptionStateStoreMigratedExceptionKafkaStreamsNotRunningExceptionStateStoreNotAvailableException


Compatibility, Deprecation, and Migration Plan

...

Rejected Alternatives

None.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


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