These are the parameters that control the behavior. (Try to set them to different values if it does not work in your environment.)
set hive.input.format=org.apache.hadoop.hive.ql.io.CombineHiveInputFormat; set mapred.min.split.size.per.node=1000000000; set mapred.min.split.size.per.rack=1000000000; set mapred.max.split.size=1000000000; set hive.merge.size.per.task=1000000000; set hive.merge.smallfiles.avgsize=1000000000; set hive.merge.size.smallfiles.avgsize=1000000000; set hive.exec.dynamic.partition.mode=nonstrict; The output size of the second job is also controlled by the split size, as shown in the first 4 lines. On Fri, Nov 19, 2010 at 10:22 AM, Leo Alekseyev <dnqu...@gmail.com> wrote: > I'm using Hadoop 0.20.2. Merge jobs (with static partitions) have > worked for me in the past. Again, what's strange here is with the > latest Hive build the merge stage appears to run, but it doesn't > actually merge -- it's a quick map-only job that, near as I can tell, > doesn't do anything. > > On Fri, Nov 19, 2010 at 6:14 AM, Dave Brondsema <dbronds...@geek.net> wrote: >> What version of Hadoop are you on? >> >> On Thu, Nov 18, 2010 at 10:48 PM, Leo Alekseyev <dnqu...@gmail.com> wrote: >>> >>> I thought I was running Hive with those changes merged in, but to make >>> sure, I built the latest trunk version. The behavior changed somewhat >>> (as in, it runs 2 stages instead of 1), but it still generates the >>> same number of files (# of files generated is equal to the number of >>> the original mappers, so I have no idea what the second stage is >>> actually doing). >>> >>> See below for query / explain query. Stage 1 runs always; Stage 3 >>> runs if hive.merge.mapfiles=true is set, but it still generates lots >>> of small files. >>> >>> The query is kind of large, but in essence it's simply >>> insert overwrite table foo partition(bar) select [columns] from >>> [table] tablesample(bucket 1 out of 10000 on rand()) where >>> [conditions]. >>> >>> >>> explain insert overwrite table hbase_prefilter3_us_sample partition >>> (ds) select >>> server_host,client_ip,time_stamp,concat(server_host,':',regexp_extract(request_url,'/[^/]+/[^/]+/([^/]+)$',1)),referrer,parse_url(referrer,'HOST'),user_agent,cookie,geoip_int(client_ip, >>> 'COUNTRY_CODE', './GeoIP.dat'),'',ds from alogs_master >>> TABLESAMPLE(BUCKET 1 OUT OF 10000 ON rand()) am_s where >>> am_s.ds='2010-11-05' and am_s.request_url rlike >>> '^/img[0-9]+/[0-9]+/[^.]+\.(png|jpg|gif|mp4|swf)$' and >>> geoip_int(am_s.client_ip, 'COUNTRY_CODE', './GeoIP.dat')='US'; >>> OK >>> ABSTRACT SYNTAX TREE: >>> (TOK_QUERY (TOK_FROM (TOK_TABREF alogs_master (TOK_TABLESAMPLE 1 >>> 10000 (TOK_FUNCTION rand)) am_s)) (TOK_INSERT (TOK_DESTINATION >>> (TOK_TAB hbase_prefilter3_us_sample (TOK_PARTSPEC (TOK_PARTVAL ds)))) >>> (TOK_SELECT (TOK_SELEXPR (TOK_TABLE_OR_COL server_host)) (TOK_SELEXPR >>> (TOK_TABLE_OR_COL client_ip)) (TOK_SELEXPR (TOK_TABLE_OR_COL >>> time_stamp)) (TOK_SELEXPR (TOK_FUNCTION concat (TOK_TABLE_OR_COL >>> server_host) ':' (TOK_FUNCTION regexp_extract (TOK_TABLE_OR_COL >>> request_url) '/[^/]+/[^/]+/([^/]+)$' 1))) (TOK_SELEXPR >>> (TOK_TABLE_OR_COL referrer)) (TOK_SELEXPR (TOK_FUNCTION parse_url >>> (TOK_TABLE_OR_COL referrer) 'HOST')) (TOK_SELEXPR (TOK_TABLE_OR_COL >>> user_agent)) (TOK_SELEXPR (TOK_TABLE_OR_COL cookie)) (TOK_SELEXPR >>> (TOK_FUNCTION geoip_int (TOK_TABLE_OR_COL client_ip) 'COUNTRY_CODE' >>> './GeoIP.dat')) (TOK_SELEXPR '') (TOK_SELEXPR (TOK_TABLE_OR_COL ds))) >>> (TOK_WHERE (and (and (= (. (TOK_TABLE_OR_COL am_s) ds) '2010-11-05') >>> (rlike (. (TOK_TABLE_OR_COL am_s) request_url) >>> '^/img[0-9]+/[0-9]+/[^.]+\.(png|jpg|gif|mp4|swf)$')) (= (TOK_FUNCTION >>> geoip_int (. (TOK_TABLE_OR_COL am_s) client_ip) 'COUNTRY_CODE' >>> './GeoIP.dat') 'US'))))) >>> >>> STAGE DEPENDENCIES: >>> Stage-1 is a root stage >>> Stage-5 depends on stages: Stage-1 , consists of Stage-4, Stage-3 >>> Stage-4 >>> Stage-0 depends on stages: Stage-4, Stage-3 >>> Stage-2 depends on stages: Stage-0 >>> Stage-3 >>> >>> STAGE PLANS: >>> Stage: Stage-1 >>> Map Reduce >>> Alias -> Map Operator Tree: >>> am_s >>> TableScan >>> alias: am_s >>> Filter Operator >>> predicate: >>> expr: (((hash(rand()) & 2147483647) % 10000) = 0) >>> type: boolean >>> Filter Operator >>> predicate: >>> expr: ((request_url rlike >>> '^/img[0-9]+/[0-9]+/[^.]+.(png|jpg|gif|mp4|swf)$') and >>> (GenericUDFGeoIP ( client_ip, 'COUNTRY_CODE', './GeoIP.dat' ) = 'US')) >>> type: boolean >>> Filter Operator >>> predicate: >>> expr: (((ds = '2010-11-05') and (request_url >>> rlike '^/img[0-9]+/[0-9]+/[^.]+.(png|jpg|gif|mp4|swf)$')) and >>> (GenericUDFGeoIP ( client_ip, 'COUNTRY_CODE', './GeoIP.dat' ) = 'US')) >>> type: boolean >>> Select Operator >>> expressions: >>> expr: server_host >>> type: string >>> expr: client_ip >>> type: int >>> expr: time_stamp >>> type: int >>> expr: concat(server_host, ':', >>> regexp_extract(request_url, '/[^/]+/[^/]+/([^/]+)$', 1)) >>> type: string >>> expr: referrer >>> type: string >>> expr: parse_url(referrer, 'HOST') >>> type: string >>> expr: user_agent >>> type: string >>> expr: cookie >>> type: string >>> expr: GenericUDFGeoIP ( client_ip, >>> 'COUNTRY_CODE', './GeoIP.dat' ) >>> type: string >>> expr: '' >>> type: string >>> expr: ds >>> type: string >>> outputColumnNames: _col0, _col1, _col2, _col3, >>> _col4, _col5, _col6, _col7, _col8, _col9, _col10 >>> File Output Operator >>> compressed: true >>> GlobalTableId: 1 >>> table: >>> input format: >>> org.apache.hadoop.mapred.TextInputFormat >>> output format: >>> org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat >>> serde: >>> org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe >>> name: hbase_prefilter3_us_sample >>> >>> Stage: Stage-5 >>> Conditional Operator >>> >>> Stage: Stage-4 >>> Move Operator >>> files: >>> hdfs directory: true >>> destination: >>> >>> hdfs://namenode.imageshack.us:9000/tmp/hive-hadoop/hive_2010-11-18_17-58-36_843_6726655151866456030/-ext-10000 >>> >>> Stage: Stage-0 >>> Move Operator >>> tables: >>> partition: >>> ds >>> replace: true >>> table: >>> input format: org.apache.hadoop.mapred.TextInputFormat >>> output format: >>> org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat >>> serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe >>> name: hbase_prefilter3_us_sample >>> >>> Stage: Stage-2 >>> Stats-Aggr Operator >>> >>> Stage: Stage-3 >>> Map Reduce >>> Alias -> Map Operator Tree: >>> >>> hdfs://namenode.imageshack.us:9000/tmp/hive-hadoop/hive_2010-11-18_17-58-36_843_6726655151866456030/-ext-10002 >>> File Output Operator >>> compressed: true >>> GlobalTableId: 0 >>> table: >>> input format: org.apache.hadoop.mapred.TextInputFormat >>> output format: >>> org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat >>> serde: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe >>> name: hbase_prefilter3_us_sample >>> >>> >>> >>> >>> On Thu, Nov 18, 2010 at 3:44 PM, Ning Zhang <nzh...@fb.com> wrote: >>> > I see. If you are using dynamic partitions, HIVE-1307 and HIVE-1622 need >>> > to be there for merging to take place. HIVE-1307 was committed to trunk on >>> > 08/25 and HIVE-1622 was committed on 09/13. The simplest way is to update >>> > your Hive trunk and rerun the query. If it still doesn't work maybe you >>> > can >>> > post your query and the result of 'explain <query>' and we can take a >>> > look. >>> > >>> > Ning >>> > >>> > On Nov 18, 2010, at 2:57 PM, Leo Alekseyev wrote: >>> > >>> >> Hi Ning, >>> >> For the dataset I'm experimenting with, the total size of the output >>> >> is 2mb, and the files are at most a few kb in size. My >>> >> hive.input.format was set to default HiveInputFormat; however, when I >>> >> set it to CombineHiveInputFormat, it only made the first stage of the >>> >> job use fewer mappers. The merge job was *still* filtered out at >>> >> runtime. I also tried set hive.mergejob.maponly=false; that didn't >>> >> have any effect. >>> >> >>> >> I am a bit at a loss what to do here. Is there a way to see what's >>> >> going on exactly using e.g. debug log levels?.. Btw, I'm also using >>> >> dynamic partitions; could that somehow be interfering with the merge >>> >> job?.. >>> >> >>> >> I'm running a relatively fresh Hive from trunk (built maybe a month >>> >> ago). >>> >> >>> >> --Leo >>> >> >>> >> On Thu, Nov 18, 2010 at 1:12 PM, Ning Zhang <nzh...@fb.com> wrote: >>> >>> The settings looks good. The parameter >>> >>> hive.merge.size.smallfiles.avgsize is used to determine at run time if a >>> >>> merge should be triggered: if the average size of the files in the >>> >>> partition >>> >>> is SMALLER than the parameter and there are more than 1 file, the merge >>> >>> should be scheduled. Can you try to see if you have any big files as >>> >>> well in >>> >>> your resulting partition? If it is because of a very large file, you >>> >>> can set >>> >>> the parameter large enough. >>> >>> >>> >>> Another possibility is that your Hadoop installation does not support >>> >>> CombineHiveInputFormat, which is used for the new merge job. Someone >>> >>> reported previously merge was not successful because of this. If that's >>> >>> the >>> >>> case, you can turn off CombineHiveInputFormat and use the old >>> >>> HiveInputFormat (though slower) by setting hive.mergejob.maponly=false. >>> >>> >>> >>> Ning >>> >>> On Nov 17, 2010, at 6:00 PM, Leo Alekseyev wrote: >>> >>> >>> >>>> I have jobs that sample (or generate) a small amount of data from a >>> >>>> large table. At the end, I get e.g. about 3000 or more files of 1kb >>> >>>> or so. This becomes a nuisance. How can I make Hive do another pass >>> >>>> to merge the output? I have the following settings: >>> >>>> >>> >>>> hive.merge.mapfiles=true >>> >>>> hive.merge.mapredfiles=true >>> >>>> hive.merge.size.per.task=256000000 >>> >>>> hive.merge.size.smallfiles.avgsize=16000000 >>> >>>> >>> >>>> After setting hive.merge* to true, Hive started indicating "Total >>> >>>> MapReduce jobs = 2". However, after generating the >>> >>>> lots-of-small-files table, Hive says: >>> >>>> Ended Job = job_201011021934_1344 >>> >>>> Ended Job = 781771542, job is filtered out (removed at runtime). >>> >>>> >>> >>>> Is there a way to force the merge, or am I missing something? >>> >>>> --Leo >>> >>> >>> >>> >>> > >>> > >> >> >> >> -- >> Dave Brondsema >> Software Engineer >> Geeknet >> >> www.geek.net >> >
