Cannot start RocksDB XTDB nodes from multiple processes on Windows

[serioga]

Expected behavior

Work on Windows simultaneously with multiple apps that use XTDB connection with RocksDB.

Actual behavior

Only first running instance can start XTDB node.
Other apps produce error:

Execution error at org.rocksdb.NativeLibraryLoader/loadLibraryFromJarToTemp (NativeLibraryLoader.java:142).
File: C:\Users\ST\AppData\Local\Temp\xtdb_rocksdb-6.12.7\librocksdbjni-win64.dll already exists and cannot be removed.

Steps to reproduce the behavior

Start XTDB node with RocksDB storage from different processes simultaneously.

[adamretter]

@serioga I think we need to eliminate any XTDB issues here really.

In your error above I see the number 6.12.7 but it also references line 142 of NativeLibraryLoader.java, however there is no such line in RocksDB 6.12.7, see: https://github.com/facebook/rocksdb/blob/v6.12.7/java/src/main/java/org/rocksdb/NativeLibraryLoader.java

What version of RocksDB are you using please?

[serioga]

What version of RocksDB are you using please?

com.xtdb/xtdb-rocksdb     {:mvn/version "1.24.3"}

which uses org.rocksdb/rocksdbjni:7.7.3 with lines in org.rocksdb.NativeLibraryLoader:

        if (temp.exists() && !temp.delete()) {
          throw new RuntimeException(
              "File: " + temp.getAbsolutePath() + " already exists and cannot be removed.");
        }

I have no idea where the xtdb_rocksdb-6.12.7 in the path comes from.

[jarohen]

@serioga, @adamretter thanks for looking into this 🙏

I believe we should be able to pass null to loadLibrary and get Rocks to manage the temp-dir for us - I'll investigate that and get back to you.

(xtdb/xtdb#3113 on our side)

[serioga]

I have no idea where the xtdb_rocksdb-6.12.7 in the path comes from.

Ah, this is from the xtdb.rocksdb.loader:

(defn- load-rocksdb-native-lib []
  (let [tmp (doto (io/file (System/getProperty "java.io.tmpdir") "xtdb_rocksdb-6.12.7") .mkdirs)
        library (io/file tmp (Environment/getJniLibraryFileName "rocksdb"))]
    (.loadLibrary (NativeLibraryLoader/getInstance) (str tmp))
    (str library)))

[refset]

With today's minor release of XTDB 1.24.4 this issue can now be closed - thanks again for the report @serioga and apologies for the noise here 🙂