cbaenziger commented on a change in pull request #785: HBASE-23239 Reporting on status of backing MOB files from client-facing cells URL: https://github.com/apache/hbase/pull/785#discussion_r343379027
########## File path: hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mob/mapreduce/MobRefReporter.java ########## @@ -0,0 +1,501 @@ +/** + * + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.hadoop.hbase.mob.mapreduce; + +import java.io.IOException; +import java.util.Arrays; +import java.util.Base64; +import java.util.HashSet; +import java.util.Set; +import java.util.UUID; + +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.conf.Configured; +import org.apache.hadoop.fs.FileStatus; +import org.apache.hadoop.fs.FileSystem; +import org.apache.hadoop.fs.Path; +import org.apache.hadoop.hbase.Cell; +import org.apache.hadoop.hbase.HBaseConfiguration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.hadoop.hbase.TableName; +import org.apache.hadoop.hbase.client.Admin; +import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor; +import org.apache.hadoop.hbase.client.Connection; +import org.apache.hadoop.hbase.client.ConnectionFactory; +import org.apache.hadoop.hbase.client.Result; +import org.apache.hadoop.hbase.client.Scan; +import org.apache.hadoop.hbase.client.TableDescriptor; +import org.apache.hadoop.hbase.io.HFileLink; +import org.apache.hadoop.hbase.io.ImmutableBytesWritable; +import org.apache.hadoop.hbase.mapreduce.TableInputFormat; +import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil; +import org.apache.hadoop.hbase.mapreduce.TableMapper; +import org.apache.hadoop.hbase.mob.MobConstants; +import org.apache.hadoop.hbase.mob.MobUtils; +import org.apache.hadoop.hbase.util.Bytes; +import org.apache.hadoop.hbase.util.EnvironmentEdgeManager; +import org.apache.hadoop.hbase.util.FSUtils; +import org.apache.hadoop.hbase.util.HFileArchiveUtil; +import org.apache.hadoop.hbase.util.Pair; +import org.apache.hadoop.io.Text; +import org.apache.hadoop.mapreduce.Job; +import org.apache.hadoop.mapreduce.Reducer; +import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat; +import org.apache.hadoop.security.UserGroupInformation; +import org.apache.hadoop.util.Tool; +import org.apache.hadoop.util.ToolRunner; +import org.apache.yetus.audience.InterfaceAudience; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Scans a given table + CF for all mob reference cells to get the list of backing mob files. + * For each referenced file we attempt to verify that said file is on the FileSystem in a place + * that the MOB system will look when attempting to resolve the actual value. + * + * The job includes counters that can help provide a rough sketch of the mob data. + * + * <pre> + * Map-Reduce Framework + * Map input records=10000 + * ... + * Reduce output records=99 + * ... + * CELLS_PER_ROW_DIGITS + * 1=10000 + * MOB + * NUM_CELLS=52364 + * PROBLEM + * IMPACTED_ROWS=338 + * MOB_FILES=2 + * PROBLEM_ROWS_PER_FILE_DIGITS + * 3=2 + * SIZE_PER_CELL_DIGITS + * 5=627 + * 6=51392 + * 7=345 + * SIZE_PER_ROW_DIGITS + * 6=6838 + * 7=3162 + * </pre> + * + * * Map-Reduce Framework:Map input records - the number of rows with mob references + * * Map-Reduce Framework:Reduce output records - the number of unique hfiles referenced + * * MOB:NUM_CELLS - the total number of mob reference cells + * * PROBLEM:IMPACTED_ROWS - the number of rows that reference hfiles with an issue + * * PROBLEM:MOB_FILES - the number of unique hfiles that have an issue + * * CELLS_PER_ROW_DIGITS: - this counter group gives a histogram of the order of magnitude of the + * number of cells in a given row by grouping by the number of digits used in each count. + * This allows us to see more about the distribution of cells than what we can determine + * with just the cell count and the row count. In this particular example we can see that + * all of our rows have somewhere between 1 - 9 cells. + * * PROBLEM_ROWS_PER_FILE_DIGITS: - this counter group gives a histogram of the order of + * magnitude of the number of rows in each of the hfiles with a problem. e.g. in the + * example there are 2 hfiles and they each have the same order of magnitude number of rows, + * namely 3 digits worth i.e. 100-999. + * * SIZE_PER_CELL_DIGITS: - this counter group gives a histogram of the order of magnitude of + * the size of mob values according to our reference cells. e.g. in the example above we + * have between 5 and 7 digits in our cell sizes i.e. 10,000 - 9,999,999 bytes. From this + * histogram we can also see that _most_ cells are 100,000 - 199,000 bytes and the smaller + * and bigger ones are outliers making up less than 2% of mob cells. + * * SIZE_PER_ROW_DIGITS: - this counter group gives a histogram of the order of magnitude of the + * size of + * + * Generates a report that gives one file status per line, with tabs dividing fields. + * + * <pre> + * RESULT OF LOOKUP FILE REF comma seperated, base64 encoded rows when there's a problem + * </pre> + * + * e.g. + * + * <pre> + * MOB DIR 09c576e28a65ed2ead0004d192ffaa382019110184b30a1c7e034573bf8580aef8393402 + * MISSING FILE 28e252d7f013973174750d483d358fa020191101f73536e7133f4cd3ab1065edf588d509 MmJiMjMyYzBiMTNjNzc0OTY1ZWY4NTU4ZjBmYmQ2MTUtNTIz,MmEzOGE0YTkzMTZjNDllNWE4MzM1MTdjNDVkMzEwNzAtODg= + * </pre> + * + * Possible results are listed; the first three indicate things are working properly. + * * MOB DIR - the reference is in the normal MOB area for the given table and CF + * * HLINK TO ARCHIVE FOR SAME TABLE - the reference is present in the archive area for this + * table and CF + * * HLINK TO ARCHIVE FOR OTHER TABLE - the reference is present in a different table and CF, + * either in the MOB or archive areas (e.g. from a snapshot restore or clone) + * * ARCHIVE WITH HLINK BUT NOT FROM OUR TABLE - the reference is currently present in the archive + * area for this table and CF, but it is kept there because a _different_ table has a + * reference to it (e.g. from a snapshot clone). If these other tables are removed then + * the file will likely be deleted unless there is a snapshot also referencing it. + * * ARCHIVE BUT NO HLINKS - the reference is currently present in the archive for this table and + * CF, but there are no references present to prevent its removal. Unless it is newer than + * the general TTL (default 5 minutes) or referenced in a snapshot it will be subject to + * cleaning. + * * ARCHIVE BUT IOE WHILE CHECKING HLINKS - Check the job logs to see why things failed while + * looking for why this file is being kept around. + * * MISSING FILE - We couldn't find the reference on the FileSystem. Either there is dataloss due Review comment: I appreciate all the info I need is here but it is really confusing; understandably the system should not be in this state too. Perhaps, leave this with a shorter statement such as, HBase should not have this happen, please file a ticket with the HBase project if you find yourself here? Or more usable, could you provide pointer to a description of how MOB works in the reference guide (containing how the server-side tag, HFileLink's and HFiles go together) and suggest the admin should walk through the states a MOB HFileLink should be in and determine where the missing piece is to manually fix it? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
