WweiL commented on code in PR #48355:
URL: https://github.com/apache/spark/pull/48355#discussion_r1871459170
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sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/RocksDB.scala:
##########
@@ -278,27 +280,159 @@ class RocksDB(
// We send snapshots that needs to be uploaded by the maintenance thread to
this queue
private val snapshotsToUploadQueue = new
ConcurrentLinkedQueue[RocksDBSnapshot]()
+ /**
+ * Read the lineage from the changelog files. It first get the changelog
reader
+ * of the correct changelog version and then read the lineage information
from the file.
+ * The changelog file is named as version_stateStoreCkptId.changelog
+ * @param version version of the changelog file, used to load changelog file.
+ * @param stateStoreCkptId uniqueId of the changelog file, used to load
changelog file.
+ * @return
+ */
+ private def getLineageFromChangelogFile(
+ version: Long,
+ stateStoreCkptId: Option[String]): Array[LineageItem] = {
+ var changelogReader: StateStoreChangelogReader = null
+ var currLineage: Array[LineageItem] = Array.empty
+ try {
+ changelogReader = fileManager.getChangelogReader(version,
stateStoreCkptId)
+ currLineage = changelogReader.lineage
+ logInfo(log"Loading lineage: " +
+ log"${MDC(LogKeys.LINEAGE, lineageManager)} from " +
+ log"changelog version: ${MDC(LogKeys.VERSION_NUM, version)} " +
+ log"uniqueId: ${MDC(LogKeys.UUID, stateStoreCkptId.getOrElse(""))}.")
+ } finally {
+ if (changelogReader != null) {
+ changelogReader.closeIfNeeded()
+ }
+ }
+ currLineage
+ }
+
+
/**
* Load the given version of data in a native RocksDB instance.
* Note that this will copy all the necessary file from DFS to local disk as
needed,
* and possibly restart the native RocksDB instance.
*/
- def load(
+ private def loadV2(
+ version: Long,
+ stateStoreCkptId: Option[String],
+ readOnly: Boolean = false): RocksDB = {
+ // An array contains lineage information from [snapShotVersion, version]
(inclusive both end)
+ var currVersionLineage: Array[LineageItem] = lineageManager.getLineage()
+ try {
+ if (loadedVersion != version || (loadedStateStoreCkptId.isEmpty ||
+ stateStoreCkptId.get != loadedStateStoreCkptId.get)) {
+ closeDB(ignoreException = false)
+
+ val (latestSnapshotVersion, latestSnapshotUniqueId) = {
+ // Special handling when version is 0.
+ // When loading the very first version (0), stateStoreCkptId does not
need to be defined
+ // because there won't be 0.changelog / 0.zip file created in RocksDB
under v2.
+ if (version == 0) {
+ assert(stateStoreCkptId.isEmpty, "stateStoreCkptId should be empty
when version is zero")
+ (0L, None)
+ // When there is a snapshot file, it is the ground truth, we can skip
+ // reconstructing the lineage from changelog file.
+ } else if (fileManager.existsSnapshotFile(version, stateStoreCkptId)) {
+ currVersionLineage = Array(LineageItem(version,
stateStoreCkptId.get))
+ lineageManager.resetLineage(currVersionLineage)
+ (version, stateStoreCkptId)
+ } else {
+ currVersionLineage = getLineageFromChangelogFile(version,
stateStoreCkptId) :+
+ LineageItem(version, stateStoreCkptId.get)
+ currVersionLineage = currVersionLineage.sortBy(_.version)
+ lineageManager.resetLineage(currVersionLineage)
+
+ val latestSnapshotVersionsAndUniqueId =
+
fileManager.getLatestSnapshotVersionAndUniqueIdFromLineage(currVersionLineage)
+ latestSnapshotVersionsAndUniqueId match {
+ case Some(pair) => pair
+ case None =>
+ logWarning("Cannot find latest snapshot based on lineage: "
+ + printLineageItems(currVersionLineage))
+ (0L, None)
Review Comment:
@siying
After the refactor requested, the error "cannot_load_base_snapshot" is
removed
```
def cannotFindBaseSnapshotCheckpoint(lineage: String): Throwable = {
new SparkException (
errorClass =
"CANNOT_LOAD_STATE_STORE.CANNOT_FIND_BASE_SNAPSHOT_CHECKPOINT",
messageParameters = Map("lineage" -> lineage),
cause = null)
}
```
When there is no valid value returned from
`getLatestSnapshotVersionAndUniqueIdFromLineage`. We use (0L, None). This is
for the following scenario:
1. load(0, None), load(1, id1), load(2, id2), load(3, id3)
2. commit -> now only 4_id4.zip file presents
3. maintenance -> 4_id4.zip file presents uploaded an becomes the groud truth
4. load(1, id1) -> Now `getLatestSnapshotVersionAndUniqueIdFromLineage`
returns nothing because the lineage loaded from 1_id1.changelog only contains
<1, id1>, but file listing returns <4, id4>
Now you have to reload from the beginning and use 0 as latestSnapshotVersion
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