[SPARK-3739] [SQL] Update the split num base on block size for table scanning

In local mode, Hadoop/Hive will ignore the "mapred.map.tasks", hence for small table file, it's always a single input split, however, SparkSQL doesn't honor that in table scanning, and we will get different result when do the Hive Compatibility test. This PR will fix that.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #2589 from chenghao-intel/source_split and squashes the following commits:

dff38e7 [Cheng Hao] Remove the extra blank line
160a2b6 [Cheng Hao] fix the compiling bug
04d67f7 [Cheng Hao] Keep 1 split for small file in table scanning

3 files changed, 517 insertions, 5 deletions

diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/TableReader.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/TableReader.scala
index f60bc3788e..c368715f7c 100644
--- a/sql/hive/src/main/scala/org/apache/spark/sql/hive/TableReader.scala
+++ b/sql/hive/src/main/scala/org/apache/spark/sql/hive/TableReader.scala
@@ -57,10 +57,15 @@ class HadoopTableReader(
     @transient hiveExtraConf: HiveConf)
   extends TableReader {
 
-  // Choose the minimum number of splits. If mapred.map.tasks is set, then use that unless
-  // it is smaller than what Spark suggests.
-  private val _minSplitsPerRDD = math.max(
-    sc.hiveconf.getInt("mapred.map.tasks", 1), sc.sparkContext.defaultMinPartitions)
+  // Hadoop honors "mapred.map.tasks" as hint, but will ignore when mapred.job.tracker is "local".
+  // https://hadoop.apache.org/docs/r1.0.4/mapred-default.html
+  //
+  // In order keep consistency with Hive, we will let it be 0 in local mode also.
+  private val _minSplitsPerRDD = if (sc.sparkContext.isLocal) {
+    0 // will splitted based on block by default.
+  } else {
+    math.max(sc.hiveconf.getInt("mapred.map.tasks", 1), sc.sparkContext.defaultMinPartitions)
+  }
 
   // TODO: set aws s3 credentials.
 
diff --git a/sql/hive/src/test/resources/golden/file_split_for_small_table-0-7a45831bf96814d9a7fc3d78fb7bd8dc b/sql/hive/src/test/resources/golden/file_split_for_small_table-0-7a45831bf96814d9a7fc3d78fb7bd8dc
new file mode 100644
index 0000000000..b70e127e82
--- /dev/null
+++ b/sql/hive/src/test/resources/golden/file_split_for_small_table-0-7a45831bf96814d9a7fc3d78fb7bd8dc
@@ -0,0 +1,500 @@
+0	val_0
+0	val_0
+0	val_0
+2	val_2
+4	val_4
+5	val_5
+5	val_5
+5	val_5
+8	val_8
+9	val_9
+10	val_10
+11	val_11
+12	val_12
+12	val_12
+15	val_15
+15	val_15
+17	val_17
+18	val_18
+18	val_18
+19	val_19
+20	val_20
+24	val_24
+24	val_24
+26	val_26
+26	val_26
+27	val_27
+28	val_28
+30	val_30
+33	val_33
+34	val_34
+35	val_35
+35	val_35
+35	val_35
+37	val_37
+37	val_37
+41	val_41
+42	val_42
+42	val_42
+43	val_43
+44	val_44
+47	val_47
+51	val_51
+51	val_51
+53	val_53
+54	val_54
+57	val_57
+58	val_58
+58	val_58
+64	val_64
+65	val_65
+66	val_66
+67	val_67
+67	val_67
+69	val_69
+70	val_70
+70	val_70
+70	val_70
+72	val_72
+72	val_72
+74	val_74
+76	val_76
+76	val_76
+77	val_77
+78	val_78
+80	val_80
+82	val_82
+83	val_83
+83	val_83
+84	val_84
+84	val_84
+85	val_85
+86	val_86
+87	val_87
+90	val_90
+90	val_90
+90	val_90
+92	val_92
+95	val_95
+95	val_95
+96	val_96
+97	val_97
+97	val_97
+98	val_98
+98	val_98
+100	val_100
+100	val_100
+103	val_103
+103	val_103
+104	val_104
+104	val_104
+105	val_105
+111	val_111
+113	val_113
+113	val_113
+114	val_114
+116	val_116
+118	val_118
+118	val_118
+119	val_119
+119	val_119
+119	val_119
+120	val_120
+120	val_120
+125	val_125
+125	val_125
+126	val_126
+128	val_128
+128	val_128
+128	val_128
+129	val_129
+129	val_129
+131	val_131
+133	val_133
+134	val_134
+134	val_134
+136	val_136
+137	val_137
+137	val_137
+138	val_138
+138	val_138
+138	val_138
+138	val_138
+143	val_143
+145	val_145
+146	val_146
+146	val_146
+149	val_149
+149	val_149
+150	val_150
+152	val_152
+152	val_152
+153	val_153
+155	val_155
+156	val_156
+157	val_157
+158	val_158
+160	val_160
+162	val_162
+163	val_163
+164	val_164
+164	val_164
+165	val_165
+165	val_165
+166	val_166
+167	val_167
+167	val_167
+167	val_167
+168	val_168
+169	val_169
+169	val_169
+169	val_169
+169	val_169
+170	val_170
+172	val_172
+172	val_172
+174	val_174
+174	val_174
+175	val_175
+175	val_175
+176	val_176
+176	val_176
+177	val_177
+178	val_178
+179	val_179
+179	val_179
+180	val_180
+181	val_181
+183	val_183
+186	val_186
+187	val_187
+187	val_187
+187	val_187
+189	val_189
+190	val_190
+191	val_191
+191	val_191
+192	val_192
+193	val_193
+193	val_193
+193	val_193
+194	val_194
+195	val_195
+195	val_195
+196	val_196
+197	val_197
+197	val_197
+199	val_199
+199	val_199
+199	val_199
+200	val_200
+200	val_200
+201	val_201
+202	val_202
+203	val_203
+203	val_203
+205	val_205
+205	val_205
+207	val_207
+207	val_207
+208	val_208
+208	val_208
+208	val_208
+209	val_209
+209	val_209
+213	val_213
+213	val_213
+214	val_214
+216	val_216
+216	val_216
+217	val_217
+217	val_217
+218	val_218
+219	val_219
+219	val_219
+221	val_221
+221	val_221
+222	val_222
+223	val_223
+223	val_223
+224	val_224
+224	val_224
+226	val_226
+228	val_228
+229	val_229
+229	val_229
+230	val_230
+230	val_230
+230	val_230
+230	val_230
+230	val_230
+233	val_233
+233	val_233
+235	val_235
+237	val_237
+237	val_237
+238	val_238
+238	val_238
+239	val_239
+239	val_239
+241	val_241
+242	val_242
+242	val_242
+244	val_244
+247	val_247
+248	val_248
+249	val_249
+252	val_252
+255	val_255
+255	val_255
+256	val_256
+256	val_256
+257	val_257
+258	val_258
+260	val_260
+262	val_262
+263	val_263
+265	val_265
+265	val_265
+266	val_266
+272	val_272
+272	val_272
+273	val_273
+273	val_273
+273	val_273
+274	val_274
+275	val_275
+277	val_277
+277	val_277
+277	val_277
+277	val_277
+278	val_278
+278	val_278
+280	val_280
+280	val_280
+281	val_281
+281	val_281
+282	val_282
+282	val_282
+283	val_283
+284	val_284
+285	val_285
+286	val_286
+287	val_287
+288	val_288
+288	val_288
+289	val_289
+291	val_291
+292	val_292
+296	val_296
+298	val_298
+298	val_298
+298	val_298
+302	val_302
+305	val_305
+306	val_306
+307	val_307
+307	val_307
+308	val_308
+309	val_309
+309	val_309
+310	val_310
+311	val_311
+311	val_311
+311	val_311
+315	val_315
+316	val_316
+316	val_316
+316	val_316
+317	val_317
+317	val_317
+318	val_318
+318	val_318
+318	val_318
+321	val_321
+321	val_321
+322	val_322
+322	val_322
+323	val_323
+325	val_325
+325	val_325
+327	val_327
+327	val_327
+327	val_327
+331	val_331
+331	val_331
+332	val_332
+333	val_333
+333	val_333
+335	val_335
+336	val_336
+338	val_338
+339	val_339
+341	val_341
+342	val_342
+342	val_342
+344	val_344
+344	val_344
+345	val_345
+348	val_348
+348	val_348
+348	val_348
+348	val_348
+348	val_348
+351	val_351
+353	val_353
+353	val_353
+356	val_356
+360	val_360
+362	val_362
+364	val_364
+365	val_365
+366	val_366
+367	val_367
+367	val_367
+368	val_368
+369	val_369
+369	val_369
+369	val_369
+373	val_373
+374	val_374
+375	val_375
+377	val_377
+378	val_378
+379	val_379
+382	val_382
+382	val_382
+384	val_384
+384	val_384
+384	val_384
+386	val_386
+389	val_389
+392	val_392
+393	val_393
+394	val_394
+395	val_395
+395	val_395
+396	val_396
+396	val_396
+396	val_396
+397	val_397
+397	val_397
+399	val_399
+399	val_399
+400	val_400
+401	val_401
+401	val_401
+401	val_401
+401	val_401
+401	val_401
+402	val_402
+403	val_403
+403	val_403
+403	val_403
+404	val_404
+404	val_404
+406	val_406
+406	val_406
+406	val_406
+406	val_406
+407	val_407
+409	val_409
+409	val_409
+409	val_409
+411	val_411
+413	val_413
+413	val_413
+414	val_414
+414	val_414
+417	val_417
+417	val_417
+417	val_417
+418	val_418
+419	val_419
+421	val_421
+424	val_424
+424	val_424
+427	val_427
+429	val_429
+429	val_429
+430	val_430
+430	val_430
+430	val_430
+431	val_431
+431	val_431
+431	val_431
+432	val_432
+435	val_435
+436	val_436
+437	val_437
+438	val_438
+438	val_438
+438	val_438
+439	val_439
+439	val_439
+443	val_443
+444	val_444
+446	val_446
+448	val_448
+449	val_449
+452	val_452
+453	val_453
+454	val_454
+454	val_454
+454	val_454
+455	val_455
+457	val_457
+458	val_458
+458	val_458
+459	val_459
+459	val_459
+460	val_460
+462	val_462
+462	val_462
+463	val_463
+463	val_463
+466	val_466
+466	val_466
+466	val_466
+467	val_467
+468	val_468
+468	val_468
+468	val_468
+468	val_468
+469	val_469
+469	val_469
+469	val_469
+469	val_469
+469	val_469
+470	val_470
+472	val_472
+475	val_475
+477	val_477
+478	val_478
+478	val_478
+479	val_479
+480	val_480
+480	val_480
+480	val_480
+481	val_481
+482	val_482
+483	val_483
+484	val_484
+485	val_485
+487	val_487
+489	val_489
+489	val_489
+489	val_489
+489	val_489
+490	val_490
+491	val_491
+492	val_492
+492	val_492
+493	val_493
+494	val_494
+495	val_495
+496	val_496
+497	val_497
+498	val_498
+498	val_498
+498	val_498
diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveTableScanSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveTableScanSuite.scala
index 54c0f017d4..a0ace91060 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveTableScanSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/hive/execution/HiveTableScanSuite.scala
@@ -44,6 +44,14 @@ class HiveTableScanSuite extends HiveComparisonTest {
       |SELECT * from part_scan_test;
     """.stripMargin)
 
+  // In unit test, kv1.txt is a small file and will be loaded as table src
+  // Since the small file will be considered as a single split, we assume
+  // Hive / SparkSQL HQL has the same output even for SORT BY
+  createQueryTest("file_split_for_small_table",
+    """
+      |SELECT key, value FROM src SORT BY key, value
+    """.stripMargin)
+
   test("Spark-4041: lowercase issue") {
     TestHive.sql("CREATE TABLE tb (KEY INT, VALUE STRING) STORED AS ORC")
     TestHive.sql("insert into table tb select key, value from src")
@@ -68,5 +76,4 @@ class HiveTableScanSuite extends HiveComparisonTest {
       === Array(Row(java.sql.Timestamp.valueOf("2014-12-11 00:00:00")),Row(null)))
     TestHive.sql("DROP TABLE timestamp_query_null")
   }
-  
 }