pvargacl commented on a change in pull request #1384:
URL: https://github.com/apache/hive/pull/1384#discussion_r467938892
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File path: ql/src/test/org/apache/hadoop/hive/ql/TestTxnCommandsForMmTable.java
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@@ -481,6 +482,61 @@ public void
testOperationsOnCompletedTxnComponentsForMmTable() throws Exception
verifyDirAndResult(0, true);
}
+ /**
+ * Impala truncates insert-only tables by writing a base directory (like
insert overwrite) containing an empty file
+ * named "_empty". Generally in Hive files beginning with an underscore are
hidden, so here we make sure that Hive
+ * reads these bases correctly.
+ *
+ * @throws Exception
+ */
+ @Test
+ public void testImpalaTruncatedMmTable() throws Exception {
+ FileSystem fs = FileSystem.get(hiveConf);
+ FileStatus[] status;
+
+ Path tblLocation = new Path(TEST_WAREHOUSE_DIR + "/" +
+ (TableExtended.MMTBL).toString().toLowerCase());
+
+ // 1. Insert two rows to an MM table
+ runStatementOnDriver("insert into " + TableExtended.MMTBL + "(a,b)
values(1,2)");
+ runStatementOnDriver("insert into " + TableExtended.MMTBL + "(a,b)
values(3,4)");
+ status = fs.listStatus(tblLocation, FileUtils.STAGING_DIR_PATH_FILTER);
+ // There should be 2 delta dirs in the location
+ Assert.assertEquals(2, status.length);
+ for (int i = 0; i < status.length; i++) {
+ Assert.assertTrue(status[i].getPath().getName().matches("delta_.*"));
+ }
+
+ // 2. Simulate Impala truncating the table: write a base dir
(base_0000003) containing an empty file.
+ // Hive will name the empty file "000000_0"
+ runStatementOnDriver("insert overwrite table " + TableExtended.MMTBL + "
select * from "
+ + TableExtended.MMTBL + " where 1=2");
+ status = fs.listStatus(tblLocation, FileUtils.STAGING_DIR_PATH_FILTER);
+ // There should be 2 delta dirs, plus 1 base dir in the location
+ Assert.assertEquals(3, status.length);
+ int baseCount = 0;
+ int deltaCount = 0;
+ for (int i = 0; i < status.length; i++) {
+ String dirName = status[i].getPath().getName();
+ if (dirName.matches("delta_.*")) {
+ deltaCount++;
+ } else {
+ baseCount++;
+ }
+ }
+ Assert.assertEquals(2, deltaCount);
+ Assert.assertEquals(1, baseCount);
+
+ // rename empty file to "_empty"
+ Path basePath = new Path(tblLocation, "base_0000003");
+ Assert.assertTrue("Rename failed",
+ fs.rename(new Path(basePath, "000000_0"), new Path(basePath,
"_empty")));
+
+ // 3. Verify query result. Selecting from a truncated table should return
nothing.
+ List<String> rs = runStatementOnDriver("select a,b from " +
TableExtended.MMTBL + " order by a,b");
+ Assert.assertEquals(Collections.emptyList(), rs);
+ }
Review comment:
Could you extend the test to run a compaction and read back the data,
just to make sure compaction also handles this file properly?
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