Deadlock in Google Storage API

Question

I'm running a spark job on Dataproc which reads lots of files from a bucket and consolidates them to one big file. I'm using google-api-services-storage 1.29.0 by shading it. Until now it worked fine, consolidating ~20-30K files. Today I tried it with about 5 times as many files and suddenly I'm getting a deadlock (at east I think I am, because it seems that all my executors are waiting indefinitely).

This is the thread dump:

org.conscrypt.NativeCrypto.SSL_read(Native Method)
org.conscrypt.NativeSsl.read(NativeSsl.java:416)
org.conscrypt.ConscryptFileDescriptorSocket$SSLInputStream.read(ConscryptFileDescriptorSocket.java:547) => holding Monitor(java.lang.Object@1638155334})
java.io.BufferedInputStream.fill(BufferedInputStream.java:246)
java.io.BufferedInputStream.read1(BufferedInputStream.java:286)
java.io.BufferedInputStream.read(BufferedInputStream.java:345) => holding Monitor(java.io.BufferedInputStream@1513035694})
sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:735)
sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:678)
sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1587) => holding Monitor(sun.net.www.protocol.https.DelegateHttpsURLConnection@995846771})
sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492) => holding Monitor(sun.net.www.protocol.https.DelegateHttpsURLConnection@995846771})
java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)
sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:347)
com.shaded.google.api.client.http.javanet.NetHttpResponse.<init>(NetHttpResponse.java:37)
com.shaded.google.api.client.http.javanet.NetHttpRequest.execute(NetHttpRequest.java:105)
com.shaded.google.api.client.http.HttpRequest.execute(HttpRequest.java:981)
com.shaded.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:419)
com.shaded.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:352)
com.shaded.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeMedia(AbstractGoogleClientRequest.java:380)
com.shaded.google.api.services.storage.Storage$Objects$Get.executeMedia(Storage.java:6189)
com.shaded.google.cloud.storage.spi.v1.HttpStorageRpc.load(HttpStorageRpc.java:584)
com.shaded.google.cloud.storage.StorageImpl$16.call(StorageImpl.java:464)
com.shaded.google.cloud.storage.StorageImpl$16.call(StorageImpl.java:461)
com.shaded.google.api.gax.retrying.DirectRetryingExecutor.submit(DirectRetryingExecutor.java:89)
com.shaded.google.cloud.RetryHelper.run(RetryHelper.java:74)
com.shaded.google.cloud.RetryHelper.runWithRetries(RetryHelper.java:51)
com.shaded.google.cloud.storage.StorageImpl.readAllBytes(StorageImpl.java:461)
com.shaded.google.cloud.storage.Blob.getContent(Blob.java:455)
my.package.with.my.StorageAPI.readFetchedLocation(StorageAPI.java:71)
...

Eventually I have to kill the job because nothing happens. Any idea what is causing it? I tried using both a ThreadLocal<Storage> and a single Storage instance in my code, it doesn't seem to make a difference.

Answer 1

The job was actually NOT deadlocked, it's just the Spark UI that for some reason didn't show any progress of the tasks until the stage finished. I thought nothing was happening but if I do a thread-dump repeatedly then I can see that it's doing stuff.

As tix suggested in a comment, it's probably advisable to implement exponential backoff when using the Storage library directly, and retry if I get a StorageException which isRetryable().