[英]How filter Scan of HBase by part of row key?
I have HBase table with row keys, which consist of text ID and timestamp, like next:我有一个带有行键的 HBase 表,它由文本 ID 和时间戳组成,如下所示:
...
string_id1.1470913344067
string_id1.1470913345067
string_id2.1470913344067
string_id2.1470913345067
...
How can I filter Scan of HBase (in Scala or Java) to get results with some string ID and timestamp more than some value?如何过滤 HBase 的扫描(在 Scala 或 Java 中)以获取具有某些字符串 ID 和时间戳的结果而不是某个值?
Thanks谢谢
Fuzzy row approach is efficient for this kind of requirement and when data is is huge : As explained by this article FuzzyRowFilter takes as parameters row key and a mask info.模糊行方法对于这种需求是有效的,并且当数据很大时:正如本文所解释的那样 FuzzyRowFilter 将行键和掩码信息作为参数。
In example above, in case we want to find last logged in users and row key format is userId_actionId_timestamp
(where userId
has fixed length of say 4 chars), the fuzzy row key we are looking for is ????_login_
.在上面的例子中,如果我们想找到最后登录的用户并且行键格式是
userId_actionId_timestamp
(其中userId
有固定长度的 4 个字符),我们要查找的模糊行键是????_login_
。 This translates into the following params for FuzzyRowKey:这转化为 FuzzyRowKey 的以下参数:
FuzzyRowFilter rowFilter = new FuzzyRowFilter(
Arrays.asList(
new Pair<byte[], byte[]>(
Bytes.toBytesBinary("\x00\x00\x00\x00_login_"),
new byte[] {1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0})));
Would suggest to go through hbase-the-definitive guide --> Client API: Advanced Features建议阅读 hbase-the-definitive 指南 --> 客户端 API:高级功能
Lets say you somehow ended up having your lines in a monadic traversable structure like List or RDD.假设你以某种方式最终将你的行放在一个像 List 或 RDD 这样的 monadic 可遍历结构中。 Now, you want to have only the strings with
id = "string_id2"
and timestamp > 1470913345000
.现在,您只想拥有
id = "string_id2"
和timestamp > 1470913345000
。
Now what is the problem here ?现在这里有什么问题? Just filter you traversable monadic structure on these two criteria.
只需根据这两个标准过滤可遍历的单子结构即可。
val filtered = listOrRddOfLines
.map(l => {
val idStr :: timestampStr :: Nil = l.split('.').toList
(idStr, timestampStr.toLong)
})
.filter({
case (idStr, timestamp) => idStr.equals("string_id2") && (timestamp > "1470913345000".toLong)
})
I resolve my problem by using to filters:我通过使用过滤器解决了我的问题:
- PrefixFilter
(I put to this filter first part of row key. In my case - string ID, for example "string_id1.") -
PrefixFilter
(我将行键的第一部分放入此过滤器。在我的情况下 - 字符串 ID,例如“string_id1”。)
- RowFilter
(I put there two parametres: first - CompareOp.GREATER_OR_EQUAL
, second - all my row key with necessary timestamp, for example "string_id1.1470913345000" -
RowFilter
(我放了两个参数:第一个 - CompareOp.GREATER_OR_EQUAL
,第二个 - 我所有的行键都带有必要的时间戳,例如“string_id1.1470913345000”
In result I get all cells with row key, which has necessary string_id
if first part, and with timestamp more or equal than I put in filter in second part.结果,我得到了所有带有行键的单元格,如果第一部分它具有必要的
string_id
,并且时间戳大于或等于我在第二部分中放入的过滤器。 It is exactly what I want.这正是我想要的。
Code snippet:代码片段:
val s = new Scan()
s.addFamily(family.getBytes)
val filterList = new FilterList()
filterList.addFilter(new PrefixFilter(Bytes.toBytes(prefixOfRowKey)))
filterList.addFilter(new RowFilter(CompareOp.GREATER_OR_EQUAL, new BinaryComparator(valueForBinaryFilter.getBytes())))
s.setFilter(filterList)
val scanner = table.getScanner(s)
Thanks to everyone who helped to find a solution.感谢所有帮助找到解决方案的人。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.