Github user yhuai commented on a diff in the pull request:
https://github.com/apache/spark/pull/1741#discussion_r15735734
--- Diff:
sql/hive/src/main/scala/org/apache/spark/sql/hive/HiveContext.scala ---
@@ -92,6 +95,64 @@ class HiveContext(sc: SparkContext) extends
SQLContext(sc) {
catalog.createTable("default", tableName,
ScalaReflection.attributesFor[A], allowExisting)
}
+ /**
+ * Analyzes the given table in the current database to generate
statistics, which will be
+ * used in query optimizations.
+ *
+ * Right now, it only supports Hive tables and it only updates the size
of a Hive table
+ * in the Hive metastore.
+ */
+ def analyze(tableName: String) {
+ val relation = catalog.lookupRelation(None, tableName) match {
+ case LowerCaseSchema(r) => r
+ case o => o
+ }
+
+ relation match {
+ case relation: MetastoreRelation => {
+ // This method is borrowed from
+ //
org.apache.hadoop.hive.ql.stats.StatsUtils.getFileSizeForTable(HiveConf, Table)
+ // in Hive 0.13.
+ // TODO: Generalize statistics collection.
+ def getFileSizeForTable(conf: HiveConf, table: Table): Long = {
+ val path = table.getPath()
+ var size: Long = 0L
+ try {
+ val fs = path.getFileSystem(conf)
+ size = fs.getContentSummary(path).getLength()
+ } catch {
+ case e: Exception =>
+ logWarning(
+ s"Failed to get the size of table ${table.getTableName} in
the " +
+ s"database ${table.getDbName} because of ${e.toString}", e)
+ size = 0L
+ }
+
+ size
+ }
+
+ val tableParameters = relation.hiveQlTable.getParameters
+ val oldTotalSize =
+
Option(tableParameters.get(StatsSetupConst.TOTAL_SIZE)).map(_.toLong).getOrElse(0L)
+ val newTotalSize = getFileSizeForTable(hiveconf,
relation.hiveQlTable)
+ // Update the Hive metastore if the total size of the table is
different than the size
+ // recorded in the Hive metastore.
+ // This logic is based on
org.apache.hadoop.hive.ql.exec.StatsTask.aggregateStats().
+ if (newTotalSize > 0 && newTotalSize != oldTotalSize) {
+ tableParameters.put(StatsSetupConst.TOTAL_SIZE,
newTotalSize.toString)
--- End diff --
Seems every time we do lookupRelation, we get a new instance of hiveQlTable
(with a new instance of underlying Hive TTable). So, I think `tableParameters`
will not be shared. The place we do metastore update is
`catalog.client.alterTable(tableFullName, new Table(hiveTTable))`. I guess the
underlying metastore can take care the concurrent update.
@liancheng can you also take a look at this analyze method?
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