问题导读
1.把生成的Lucene索引,拷贝至本地磁盘有哪些缺点?
2.Solr与ElasticSearch和Lucene相比,有什么优点?
在上篇文章中介绍了,如何使用Apache Pig与Lucene集成,还不知道的道友们,可以先看上篇,熟悉下具体的流程。
在与Lucene集成过程中,我们发现最终还要把生成的Lucene索引,拷贝至本地磁盘,才能提供检索服务,这样以来,比较繁琐,而且有以下几个缺点:
(一)在生成索引以及最终能提供正常的服务之前,索引经过多次落地操作,这无疑会给磁盘和网络IO,带来巨大影响
(二)Lucene的Field的配置与其UDF函数的代码耦合性过强,而且提供的配置也比较简单,不太容易满足,灵活多变的检索需求和服务,如果改动索引配置,则有可能需要重新编译源码。
(三)对Hadoop的分布式存储系统HDFS依赖过强,如果使用与Lucene集成,那么则意味着你提供检索的Web服务器,则必须跟hadoop的存储节点在一个机器上,否则,无法从HDFS上下拉索引,除非你自己写程序,或使用scp再次从目标机传输,这样无疑又增加了,系统的复杂性。
鉴于有以上几个缺点,所以建议大家使用Solr或ElasticSearch这样的封装了Lucene更高级的API框架,那么Solr与ElasticSearch和Lucene相比,又有什么优点呢?
(1)在最终的写入数据时,我们可以直接最终结果写入solr或es,同时也可以在HDFS上保存一份,作为灾备。
(2)使用了solr或es,这时,我们字段的配置完全与UDF函数代码无关,我们的任何字段配置的变动,都不会影响Pig的UDF函数的代码,而在UDF函数里,唯一要做的,就是将最终数据,提供给solr和es服务。
(3)solr和es都提供了restful风格的http操作方式,这时候,我们的检索集群完全可以与Hadoop集群分离,从而让他们各自都专注自己的服务。
下面,散仙就具体说下如何使用Pig和Solr集成?
(1)依旧访问这个地址下载源码压缩包。
(2)提取出自己想要的部分,在eclipse工程中,修改定制适合自己环境的的代码(Solr版本是否兼容?hadoop版本是否兼容?,Pig版本是否兼容?)。
(3)使用ant重新打包成jar
(4)在pig里,注册相关依赖的jar包,并使用索引存储
注意,在github下载的压缩里直接提供了对SolrCloud模式的提供,而没有提供,普通模式的函数,散仙在这里稍作修改后,可以支持普通模式的Solr服务,代码如下:
SolrOutputFormat函数
- package com.pig.support.solr;
-
-
-
- import java.io.IOException;
- import java.util.ArrayList;
- import java.util.List;
- import java.util.concurrent.Executors;
- import java.util.concurrent.ScheduledExecutorService;
- import java.util.concurrent.TimeUnit;
-
- import org.apache.hadoop.io.Writable;
- import org.apache.hadoop.mapreduce.JobContext;
- import org.apache.hadoop.mapreduce.OutputCommitter;
- import org.apache.hadoop.mapreduce.RecordWriter;
- import org.apache.hadoop.mapreduce.TaskAttemptContext;
- import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
- import org.apache.solr.client.solrj.SolrServer;
- import org.apache.solr.client.solrj.SolrServerException;
- import org.apache.solr.client.solrj.impl.CloudSolrServer;
- import org.apache.solr.client.solrj.impl.HttpSolrServer;
- import org.apache.solr.common.SolrInputDocument;
- /**
- * @author qindongliang
- * 支持SOlr的SolrOutputFormat
- * 如果你想了解,或学习更多这方面的
- *
- * */
- public class SolrOutputFormat extends
- FileOutputFormat<Writable, SolrInputDocument> {
-
- final String address;
- final String collection;
-
- public SolrOutputFormat(String address, String collection) {
- this.address = address;
- this.collection = collection;
- }
-
- @Override
- public RecordWriter<Writable, SolrInputDocument> getRecordWriter(
- TaskAttemptContext ctx) throws IOException, InterruptedException {
- return new SolrRecordWriter(ctx, address, collection);
- }
-
-
- @Override
- public synchronized OutputCommitter getOutputCommitter(
- TaskAttemptContext arg0) throws IOException {
- return new OutputCommitter(){
-
- @Override
- public void abortTask(TaskAttemptContext ctx) throws IOException {
-
- }
-
- @Override
- public void commitTask(TaskAttemptContext ctx) throws IOException {
-
- }
-
- @Override
- public boolean needsTaskCommit(TaskAttemptContext arg0)
- throws IOException {
- return true;
- }
-
- @Override
- public void setupJob(JobContext ctx) throws IOException {
-
- }
-
- @Override
- public void setupTask(TaskAttemptContext ctx) throws IOException {
-
- }
-
-
- };
- }
-
-
- /**
- * Write out the LuceneIndex to a local temporary location.<br/>
- * On commit/close the index is copied to the hdfs output directory.<br/>
- *
- */
- static class SolrRecordWriter extends RecordWriter<Writable, SolrInputDocument> {
- /**Solr的地址*/
- SolrServer server;
- /**批处理提交的数量**/
- int batch = 5000;
-
- TaskAttemptContext ctx;
-
- List<SolrInputDocument> docs = new ArrayList<SolrInputDocument>(batch);
- ScheduledExecutorService exec = Executors.newSingleThreadScheduledExecutor();
- /**
- * Opens and forces connect to CloudSolrServer
- *
- * @param address
- */
- public SolrRecordWriter(final TaskAttemptContext ctx, String address, String collection) {
- try {
- this.ctx = ctx;
- server = new HttpSolrServer(address);
-
- exec.scheduleWithFixedDelay(new Runnable(){
- public void run(){
- ctx.progress();
- }
- }, 1000, 1000, TimeUnit.MILLISECONDS);
- } catch (Exception e) {
- RuntimeException exc = new RuntimeException(e.toString(), e);
- exc.setStackTrace(e.getStackTrace());
- throw exc;
- }
- }
-
-
- /**
- * On close we commit
- */
- @Override
- public void close(final TaskAttemptContext ctx) throws IOException,
- InterruptedException {
-
- try {
-
- if (docs.size() > 0) {
- server.add(docs);
- docs.clear();
- }
-
- server.commit();
- } catch (SolrServerException e) {
- RuntimeException exc = new RuntimeException(e.toString(), e);
- exc.setStackTrace(e.getStackTrace());
- throw exc;
- } finally {
- server.shutdown();
- exec.shutdownNow();
- }
-
- }
-
- /**
- * We add the indexed documents without commit
- */
- @Override
- public void write(Writable key, SolrInputDocument doc)
- throws IOException, InterruptedException {
- try {
- docs.add(doc);
- if (docs.size() >= batch) {
- server.add(docs);
- docs.clear();
- }
- } catch (SolrServerException e) {
- RuntimeException exc = new RuntimeException(e.toString(), e);
- exc.setStackTrace(e.getStackTrace());
- throw exc;
- }
- }
-
- }
- }
复制代码
SolrStore函数
- package com.pig.support.solr;
-
-
-
- import java.io.IOException;
- import java.util.Properties;
-
- import org.apache.hadoop.fs.Path;
- import org.apache.hadoop.io.Writable;
- import org.apache.hadoop.mapreduce.Job;
- import org.apache.hadoop.mapreduce.OutputFormat;
- import org.apache.hadoop.mapreduce.RecordWriter;
- import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
- import org.apache.pig.ResourceSchema;
- import org.apache.pig.ResourceSchema.ResourceFieldSchema;
- import org.apache.pig.ResourceStatistics;
- import org.apache.pig.StoreFunc;
- import org.apache.pig.StoreMetadata;
- import org.apache.pig.data.Tuple;
- import org.apache.pig.impl.util.UDFContext;
- import org.apache.pig.impl.util.Utils;
- import org.apache.solr.common.SolrInputDocument;
-
- /**
- *
- * Create a lucene index
- *
- */
- public class SolrStore extends StoreFunc implements StoreMetadata {
-
- private static final String SCHEMA_SIGNATURE = "solr.output.schema";
-
- ResourceSchema schema;
- String udfSignature;
- RecordWriter<Writable, SolrInputDocument> writer;
-
- String address;
- String collection;
-
- public SolrStore(String address, String collection) {
- this.address = address;
- this.collection = collection;
- }
-
- public void storeStatistics(ResourceStatistics stats, String location,
- Job job) throws IOException {
- }
-
- public void storeSchema(ResourceSchema schema, String location, Job job)
- throws IOException {
- }
-
- @Override
- public void checkSchema(ResourceSchema s) throws IOException {
- UDFContext udfc = UDFContext.getUDFContext();
- Properties p = udfc.getUDFProperties(this.getClass(),
- new String[] { udfSignature });
- p.setProperty(SCHEMA_SIGNATURE, s.toString());
- }
-
- public OutputFormat<Writable, SolrInputDocument> getOutputFormat()
- throws IOException {
- // not be used
- return new SolrOutputFormat(address, collection);
- }
-
- /**
- * Not used
- */
- @Override
- public void setStoreLocation(String location, Job job) throws IOException {
- FileOutputFormat.setOutputPath(job, new Path(location));
- }
-
- @Override
- public void setStoreFuncUDFContextSignature(String signature) {
- this.udfSignature = signature;
- }
-
- @SuppressWarnings({ "unchecked", "rawtypes" })
- @Override
- public void prepareToWrite(RecordWriter writer) throws IOException {
- this.writer = writer;
- UDFContext udc = UDFContext.getUDFContext();
- String schemaStr = udc.getUDFProperties(this.getClass(),
- new String[] { udfSignature }).getProperty(SCHEMA_SIGNATURE);
-
- if (schemaStr == null) {
- throw new RuntimeException("Could not find udf signature");
- }
-
- schema = new ResourceSchema(Utils.getSchemaFromString(schemaStr));
-
- }
-
- /**
- * Shamelessly copied from : https://issues.apache.org/jira/secure/attachment/12484764/NUTCH-1016-2.0.patch
- * @param input
- * @return
- */
- private static String stripNonCharCodepoints(String input) {
- StringBuilder retval = new StringBuilder(input.length());
- char ch;
-
- for (int i = 0; i < input.length(); i++) {
- ch = input.charAt(i);
-
- // Strip all non-characters
- // http://unicode.org/cldr/utility/list-unicodeset.jsp?a=[:Noncharacter_Code_Point=True:]
- // and non-printable control characters except tabulator, new line
- // and carriage return
- if (ch % 0x10000 != 0xffff && // 0xffff - 0x10ffff range step
- // 0x10000
- ch % 0x10000 != 0xfffe && // 0xfffe - 0x10fffe range
- (ch <= 0xfdd0 || ch >= 0xfdef) && // 0xfdd0 - 0xfdef
- (ch > 0x1F || ch == 0x9 || ch == 0xa || ch == 0xd)) {
-
- retval.append(ch);
- }
- }
-
- return retval.toString();
- }
-
- @Override
- public void putNext(Tuple t) throws IOException {
-
- final SolrInputDocument doc = new SolrInputDocument();
-
- final ResourceFieldSchema[] fields = schema.getFields();
- int docfields = 0;
-
- for (int i = 0; i < fields.length; i++) {
- final Object value = t.get(i);
-
- if (value != null) {
- docfields++;
- doc.addField(fields[i].getName().trim(), stripNonCharCodepoints(value.toString()));
- }
-
- }
-
- try {
- if (docfields > 0)
- writer.write(null, doc);
- } catch (InterruptedException e) {
- Thread.currentThread().interrupt();
- return;
- }
-
- }
-
- }
复制代码
Pig脚本如下:
- --注册依赖文件的jar包
- REGISTER ./dependfiles/tools.jar;
-
- --注册solr相关的jar包
- REGISTER ./solrdependfiles/pigudf.jar;
- REGISTER ./solrdependfiles/solr-core-4.10.2.jar;
- REGISTER ./solrdependfiles/solr-solrj-4.10.2.jar;
- REGISTER ./solrdependfiles/httpclient-4.3.1.jar
- REGISTER ./solrdependfiles/httpcore-4.3.jar
- REGISTER ./solrdependfiles/httpmime-4.3.1.jar
- REGISTER ./solrdependfiles/noggit-0.5.jar
-
-
- --加载HDFS数据,并定义scheaml
- a = load '/tmp/data' using PigStorage(',') as (sword:chararray,scount:int);
-
- --存储到solr中,并提供solr的ip地址和端口号
- store d into '/user/search/solrindextemp' using com.pig.support.solr.SolrStore('http://localhost:8983/solr/collection1','collection1');
- ~
- ~
- ~
复制代码
配置成功之后,我们就可以运行程序,加载HDFS上数据,经过计算处理之后,并将最终的结果,存储到Solr之中,截图如下:
成功之后,我们就可以很方便的在solr中进行毫秒级别的操作了,例如各种各样的全文查询,过滤,排序统计等等!
同样的方式,我们也可以将索引存储在ElasticSearch中,关于如何使用Pig和ElasticSearch集成,散仙也会在后面的文章中介绍,敬请期待!
公众号:我是攻城师(woshigcs)
转自:散仙
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