aboutsummaryrefslogtreecommitdiffstats
path: root/README.md
blob: f76bd9171c910b66b47c5c390efba3565dbe8979 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
SpyGlass
========

Cascading and Scalding wrapper for HBase with advanced read and write features. JDBC wrapper is recently added to support SQL in taps. Insert/Update/Upserts (Update on Duplicates) are supported with MultiRowInserts & Batch Modes.

Prevent Hot Spotting by the use of transparent key prefixes.

Changes
=======
- Compatible with Scalding 0.9.1 since version 4.2rc2
- Added JDBC Tap Functionality
- Added Delete Functionality
- Added Region grouping of splits
- Migrated maven repo to local subdirectory. See below.

Building
========

	$ mvn clean install -U
	$ mvn deploy

	Requires Maven 3.x.x

To use SpyGlass as a dependency use the following repository

```xml
<repositories>
  <repository>
    <id>conjars.org</id>
    <url>http://conjars.org/repo</url>
  </repository>
</repositories>
```

For Scalding 0.10.0 use :

```xml
<dependencies>
  <dependency>
    <groupId>parallelai</groupId>
    <artifactId>parallelai.spyglass</artifactId>
    <version>2.10_0.10_4.3</version>
  </dependency>
</dependencies>
```

For Scalding 0.9.1 use :

```xml
<dependencies>
  <dependency>
    <groupId>parallelai</groupId>
    <artifactId>parallelai.spyglass</artifactId>
    <version>2.10_0.9_4.3</version>
  </dependency>
</dependencies>
```

or for earlier versions :

```xml
<dependencies>
  <dependency>
    <groupId>parallelai</groupId>
    <artifactId>parallelai.spyglass</artifactId>
    <version>2.9.3_4.1.0</version>
  </dependency>
</dependencies>
```

and

```xml
<dependencies>
  <dependency>
    <groupId>parallelai</groupId>
    <artifactId>parallelai.spyglass</artifactId>
    <version>2.10.2_4.1.0</version>
  </dependency>
</dependencies>
```



1. Read Mode Features
=====================

HBaseSource supports modes namely **GET_LIST**, **SCAN_RANGE** and **SCAN_ALL**. Use the **_sourceMode_** parameter to select the source mode.

  - **GET_LIST** -> Provide a list of keys to retrieve from the HBase table
  - **SCAN_RANGE** -> Provide a start and stop key (inclusive) to get out of the HBase table.
  - **SCAN_ALL** -> Get all rows form the HBase Table

GET_LIST
--------
Requires the **_keyList_** parameter to be specified as well.

(e.g.)

```scala
val hbs2 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.GET_LIST, keyList = List("5003914", "5000687", "5004897"))
```

Additionally, the **_versions_** parameter can be used to retrieve more than one version of the row.

(e.g.)

```scala
val hbs2 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.GET_LIST,
  versions = 5,
  keyList = List("5003914", "5000687", "5004897"))
```

SCAN_RANGE
----------
Scan range uses the optional **_startKey_** and **_stopKey_** parameters to specify the range of keys to extract; both keys are inclusive.

if:
 - Only **_startKey_** provided -> All rows from **_startKey_** till **END OF TABLE** are returned
 - Only **_stopKey_** provided -> All rows from **START OF TABLE** till **_stopKey_** are returned
 - Neither provided -> All rows in table are returned.

(e.g.)

```scala
val hbs4 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.SCAN_RANGE, stopKey = "5003914")
  .read
  .write(Tsv(output.format("scan_range_to_end")))

val hbs5 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.SCAN_RANGE, startKey = "5003914")
  .read
  .write(Tsv(output.format("scan_range_from_start")))

val hbs6 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.SCAN_RANGE, startKey = "5003914", stopKey = "5004897")
  .read
  .write(Tsv(output.format("scan_range_between")))
```

SCAN_ALL
--------
Returns all rows in the table

(e.g.)

```scala
val hbs2 = new HBaseSource(
  "table_name",
  "quorum_name:2181",
  'key,
  Array("column_family"),
  Array('column_name),
  sourceMode = SourceMode.SCAN_ALL)
```

2. Write Mode Features
======================

HBaseSource supports writing at a particular time stamp i.e. a version.

The time dimension can be added to the row by using the **_timestamp_** parameter. If the parameter is not present the current time is used.

(e.g.)

```scala
pipe.write(new HBaseSource( "table_name",
  "quorum_name:2181",
  'key,
  TABLE_SCHEMA.tail.map((x: Symbol) => "data").toArray,
  TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)).toArray,
  timestamp = Platform.currentTime ))
```


3. Region Hot Spot Prevention
=============================

Region hot spotting is a common problem with HBase. Spy Glass uses key prefix salting to avoid this.
The row key is prefixed with the last byte followed by a '_' (underscore) character.

(e.g.)

```
Original Row Key   ->  Becomes
SPYGLASS           ->  S_SPYGLASS
12345678           ->  8_12345678
```

Conversion to and from salted keys is done automatically.

Setting the **_useSalt_** parameter to **true** enables this functionality


(e.g.)

```scala
val TABLE_SCHEMA = List('key, 'salted, 'unsalted)

val hbase07 = new HBaseSource( "table_name",
  "quorum_name:2181", 'key,
  TABLE_SCHEMA.tail.map((x: Symbol) => "data").toArray,
  TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)).toArray,
  sourceMode = SourceMode.SCAN_RANGE, startKey = "11445", stopKey = "11455",
  useSalt = true, prefixList = "0123456789" )
.read

// Convert from ImmutableBytesWritable to String
.fromBytesWritable( TABLE_SCHEMA )

.write(TextLine("saltTesting/ScanRangePlusSalt10"))

// Convert from String to ImmutableBytesWritable
.toBytesWritable( TABLE_SCHEMA )

.write(new HBaseSource( "table_name",
  "quorum_name:2181", 'key,
  TABLE_SCHEMA.tail.map((x: Symbol) => "data").toArray,
  TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)).toArray,
  useSalt = true ))
```


Setting the **_prefixList_** parameter to the available prefixes can increase the read performance quite a bit.

4. Pipe Conversion Implicits
============================

HBaseSource will always read or write fields of type **_ImmutableBytesWritable_**. The supplied **_HBasePipeConversions_** trait is used to convert to and from **_String_** to **_ImmutableBytesWritable_**

Add the trait to the job class and start using the conversions in the pipe directly

(e.g.)

```scala
class HBaseSaltTester (args: Args) extends JobBase(args) with HBasePipeConversions {
  val TABLE_SCHEMA = List('key, 'salted, 'unsalted)

  val hbase07 =
  new HBaseSource( "table_name",
    "quorum_name:2181", 'key,
    TABLE_SCHEMA.tail.map((x: Symbol) => "data").toArray,
    TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)).toArray,
    sourceMode = SourceMode.SCAN_RANGE, startKey = "11445", stopKey = "11455",
    useSalt = true, prefixList = "0123456789" )
  .read

  // Convert from ImmutableBytesWritable to String
  .fromBytesWritable( TABLE_SCHEMA )

  .write(TextLine("saltTesting/ScanRangePlusSalt10"))

  // Convert from String to ImmutableBytesWritable
  .toBytesWritable( TABLE_SCHEMA )

  .write(new HBaseSource( "table_name",
    "quorum_name:2181", 'key,
    TABLE_SCHEMA.tail.map((x: Symbol) => "data").toArray,
    TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)).toArray,
    useSalt = true ))
}
```


5. Raw HBase Tap and Source
===========================
HBaseRawSource is an alternative HBase source implementation that provides two main features:
* Ability to provide a custom scan object.
* Passing the row object to the mapper to allow full customized processing (without the need to declare in advance the read columns).

**Passing a scan object**

`HBaseRawSource` object provides a helper function to encode a scan object as a base64 string, which you can pass to the source.
e.g.

```scala
val scan = new Scan
val key = "my_key_prefix"
scan.setStartRow(Bytes.toBytes(key))
scan.setFilter(new PrefixFilter(Bytes.toBytes(key)))
val scanner = HBaseRawSource.convertScanToString(scan)
val hbaseSource = new HBaseRawSource("MY-TABLE", "hbase-local", Array("col-family"), base64Scan = scanner)
```

**Processing the rows**

The mapper function gets from HBaseRawSource a tuple containing two fields: (rowkey, row).
The first field is the row key, the second is the row Result object. You can then process the row as needed.
The sink expects a rowkey field in the tuple it gets to use as a row key (it doesn't have to be the same as the one emitted by the source).
It will then write the output fields (except the rowkey) as columns under the provided family, using the field name as the column name.
You can also provide the field name as a full qualifier (family:column) to specify a different family than was declared in the source.
e.g.

```scala
val hbaseOut = new HBaseRawSource("MY_RESULTS", "hbase-local", Array("out-family"), writeNulls=false, sinkMode = SinkMode.REPLACE)
hbaseSource.read
.mapTo(('rowkey, 'row) -> ('rowkey, "different_family:col1", 'col2)) {
  x: (ImmutableBytesWritable, Result) => {
    val (rowkey, row) = x
    val col1Times2 = Bytes.toInt(row.getValue(Bytes.toBytes("col-family"),
                                 Bytes.toBytes("col1"))) * 2;
    val col2 = row.getValue(Bytes.toBytes("col-family"), Bytes.toBytes("col2"));
    (rowkey, col1Times2, col2)
  }
}
.write(hbaseOut)
```

6. Jdbc Tap and Source
===========================

To be added soon.

e.g.

```scala
val jdbcSourceRead = new JDBCSource(
  "TABLE_01",
  "com.mysql.jdbc.Driver",
  "jdbc:mysql://localhost:3306/db?zeroDateTimeBehavior=convertToNull",
  "root",
  "password",
  List("ID", "TEST_COLUMN1", "TEST_COLUMN2", "TEST_COLUMN3"),
  List("bigint(20)", "varchar(45)", "varchar(45)", "bigint(20)"),
  List("id"),
  new Fields("key", "column1", "column2", "column3"),
  null, null, null)

val jdbcSourceWrite = new JDBCSource(
  "TABLE_01",
  "com.mysql.jdbc.Driver",
  "jdbc:mysql://localhost:3306/db?zeroDateTimeBehavior=convertToNull",
  "root",
  "password",
  List("ID", "TEST_COLUMN1", "TEST_COLUMN2", "TEST_COLUMN3"),
  List("bigint(20)", "varchar(45)", "varchar(45)", "bigint(20)"),
  List("id"),
  new Fields("key", "column1", "column2", "column3"),
  null, null, null)
```

7. HBase Delete Functionality
=============================

Delete functionality has been added to SpyGlass version 4.1.0 onwards. Below is an example of how to use it.

The feature can be enable by using the parameter sinkMode = SinkMode.REPLACE in the HBaseSource
You can use sinkMode = SinkMode.UPDATE to add to the HBaseTable as usual.

e.g.

```scala
val eraser = toIBW(input, TABLE_SCHEMA)
  .write(new HBaseSource( "_TEST.SALT.01", quorum, 'key,
  TABLE_SCHEMA.tail.map((x: Symbol) => "data"),
  TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)), sinkMode = SinkMode.REPLACE ))
```

All rows with the key will be deleted. This includes all versions too.

8. Regional Split Group in Scan and Get
=======================================

This functionality reduces the number of mappers significantly when using hot spot prevention with prefixes.

This feature can be activated by using inputSplitType = SplitType.REGIONAL
You can use inputSplitType = SplitType.GRANULAR to use the previous functionality as is.

e.g.

```scala
val hbase04 = new HBaseSource( "_TEST.SALT.01", quorum, 'key,
  TABLE_SCHEMA.tail.map((x: Symbol) => "data"),
  TABLE_SCHEMA.tail.map((x: Symbol) => new Fields(x.name)),
  sourceMode = SourceMode.SCAN_RANGE, startKey = sttKeyP, stopKey = stpKeyP,
  inputSplitType = splitType).read
  .fromBytesWritable(TABLE_SCHEMA )
  .map(('key, 'salted, 'unsalted) -> 'testData) {x: (String, String, String) => List(x._1, x._2, x._3)}
  .project('testData)
  .write(TextLine("saltTesting/ScanRangeNoSalt01"))
  .groupAll(group => group.toList[List[List[String]]]('testData -> 'testData))
```

9. Complete example
===================

If using Maven - create a pom.xml

```xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>mygroup</groupId>
  <artifactId>myartifact</artifactId>
  <version>1.0-SNAPSHOT</version>
  <name>myname</name>

  <repositories>
    <repository>
      <id>conjars.org</id>
      <url>http://conjars.org/repo</url>
    </repository>
  </repositories>

  <dependencies>
    <dependency>
      <groupId>parallelai</groupId>
      <artifactId>parallelai.spyglass</artifactId>
      <!-- Scala: 2.10 | Scalding: 0.10.0 | SpyGlass: 4.3 -->
      <version>2.10_0.10_4.3</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.scala-tools</groupId>
        <artifactId>maven-scala-plugin</artifactId>
        <version>2.15.2</version>
        <executions>
          <execution>
            <id>scala-compile</id>
            <goals>
              <goal>compile</goal>
              <goal>testCompile</goal>
            </goals>
            <configuration>
              <args>
                <arg>-make:transitive</arg>
                <arg>-dependencyfile</arg>
                <arg>${project.build.directory}/.scala_dependencies</arg>
              </args>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

</project>
```

A single dependency brings in Scalding 0.10.0 (in this example)

```scala
import com.twitter.scalding.{TextLine, Job, Args}
import parallelai.spyglass.hbase.{HBaseSource, HBasePipeConversions}
import cascading.tuple.Fields
import parallelai.spyglass.hbase.HBaseConstants.SourceMode

/**
 * Before executing this example, have a working HBase
 * (see https://github.com/kijiproject/kiji-bento for a standalone zero-configuration HBase micro-cluster)
 * , and
 *
 * $ hbase shell
 *
 * hbase(main):003:0> create 'spyglass.hbase.test1' , 'data'
 * hbase(main):006:0> put 'spyglass.hbase.test1' , 'row1' , 'data:column1' , 'value1'
 * hbase(main):007:0> put 'spyglass.hbase.test1' , 'row2' , 'data:column1' , 'value2'
 * hbase(main):008:0> put 'spyglass.hbase.test1' , 'row3' , 'data:column1' , 'value3'
 * hbase(main):009:0> scan 'spyglass.hbase.test1'
 *
 */
class HBaseTest(args: Args) extends Job(args) with HBasePipeConversions {

  val SCHEMA = List('key, 'column1)
  val tableName = "spyglass.hbase.test1"
  val hbaseHost = "localhost:2181"

  val data = new HBaseSource(
    tableName,
    hbaseHost,
    SCHEMA.head,
    SCHEMA.tail.map((x: Symbol) => "data"),
    SCHEMA.tail.map((x: Symbol) => new Fields(x.name)),
    sourceMode = SourceMode.SCAN_ALL)
    .read
    .fromBytesWritable(SCHEMA)
    .debug
    .write(TextLine("test_hbase"))
}
```