weizhengte commented on code in PR #8859: URL: https://github.com/apache/incubator-doris/pull/8859#discussion_r843929072
########## fe/fe-core/src/main/java/org/apache/doris/statistics/StatisticsJobScheduler.java: ########## @@ -33,31 +49,217 @@ Switch job state from pending to scheduling. */ public class StatisticsJobScheduler extends MasterDaemon { + private static final Logger LOG = LogManager.getLogger(StatisticsJobScheduler.class); - public Queue<StatisticsJob> pendingJobQueue = Queues.newLinkedBlockingQueue(); + /** + * Different statistics need to be collected for the jobs submitted by users. + * if all statistics be collected at the same time, the cluster may be overburdened + * and normal query services may be affected. Therefore, we put the jobs into the queue + * and schedule them one by one, and finally divide each job to several subtasks and execute them. + */ + public final Queue<StatisticsJob> pendingJobQueue = Queues.newLinkedBlockingQueue(Config.cbo_max_statistics_job_num); public StatisticsJobScheduler() { super("Statistics job scheduler", 0); } @Override protected void runAfterCatalogReady() { - // TODO - StatisticsJob pendingJob = pendingJobQueue.peek(); - // step0: check job state again - // step1: divide statistics job to task - List<StatisticsTask> statisticsTaskList = divide(pendingJob); - // step2: submit - Catalog.getCurrentCatalog().getStatisticsTaskScheduler().addTasks(statisticsTaskList); + StatisticsJob pendingJob = this.pendingJobQueue.peek(); + if (pendingJob != null) { + this.pendingJobQueue.remove(); + StatisticsJob.JobState jobState = pendingJob.getJobState(); + // job scheduler is only responsible for moving the job from pending -> scheduler + if (jobState == StatisticsJob.JobState.PENDING) { + pendingJob.setScheduleTime(System.currentTimeMillis()); + try { + List<StatisticsTask> tasks = this.divide(pendingJob); + ArrayList<StatisticsTask> list = Lists.newArrayList(); + for (StatisticsTask task : tasks) { + // TODO now only support meta task + if (task instanceof MetaStatisticsTask){ + list.add(task); + } + } + pendingJob.setTasks(list); + Catalog.getCurrentCatalog().getStatisticsTaskScheduler().addTasks(list); + pendingJob.setJobState(StatisticsJob.JobState.SCHEDULING); + } catch (DdlException e) { + pendingJob.setJobState(StatisticsJob.JobState.FAILED); + LOG.info("Failed to schedule the statistical job. " + e.getMessage()); + } + } + } } public void addPendingJob(StatisticsJob statisticsJob) throws IllegalStateException { - pendingJobQueue.add(statisticsJob); + this.pendingJobQueue.add(statisticsJob); + } + + /** + * Statistics tasks are of the following types: + * table: + * - row_count: table row count are critical in estimating cardinality and memory usage of scan nodes. + * - data_size: table size, not applicable to CBO, mainly used to monitor and manage table size. + * column: + * - num_distinct_value: used to determine the selectivity of an equivalent expression. + * - min: The minimum value. + * - max: The maximum value. + * - num_nulls: number of nulls. + * - avg_col_len: the average length of a column, in bytes, is used for memory and network IO evaluation. + * - max_col_len: the Max length of the column, in bytes, is used for memory and network IO evaluation. + * <p> + * Divide: + * - min, max, ndv: These three full indicators are collected by a sub-task. + * - max_col_lens, avg_col_lens: Two sampling indicators were collected by a sub-task. + * <p> + * If the table row-count is greater than the maximum number of Be scans for a single BE, + * we'll divide subtasks by partition. relevant values(3700000000L&600000000L) are derived from test. + * <p> + * Eventually, we will get several subtasks of the following types: + * + * @throws DdlException DdlException + * @see MetaStatisticsTask + * @see SampleSQLStatisticsTask + * @see SQLStatisticsTask + */ + private List<StatisticsTask> divide(StatisticsJob statisticsJob) throws DdlException { + long jobId = statisticsJob.getId(); + long dbId = statisticsJob.getDbId(); + Database db = Catalog.getCurrentCatalog().getDbOrDdlException(dbId); + Set<Long> tableIds = statisticsJob.relatedTableId(); + Map<Long, List<String>> tableIdToColumnName = statisticsJob.getTableIdToColumnName(); + List<StatisticsTask> tasks = statisticsJob.getTasks(); + List<Long> backendIds = Catalog.getCurrentSystemInfo().getBackendIds(true); + + for (Long tableId : tableIds) { + Table tbl = db.getTableOrDdlException(tableId); + long rowCount = tbl.getRowCount(); + List<Long> partitionIds = ((OlapTable) tbl).getPartitionIds(); + List<String> columnNameList = tableIdToColumnName.get(tableId); + + // step 1: generate data_size task + StatsCategoryDesc dataSizeCategory = this.getTblStatsCategoryDesc(dbId, tableId); + StatsGranularityDesc dataSizeGranularity = this.getTblStatsGranularityDesc(tableId); + MetaStatisticsTask dataSizeTask = new MetaStatisticsTask(jobId, + dataSizeGranularity, dataSizeCategory, Collections.singletonList(StatsType.DATA_SIZE)); + tasks.add(dataSizeTask); + + // step 2: generate row_count task + KeysType keysType = ((OlapTable) tbl).getKeysType(); + if (keysType == KeysType.DUP_KEYS) { + StatsCategoryDesc rowCountCategory = this.getTblStatsCategoryDesc(dbId, tableId); + StatsGranularityDesc rowCountGranularity = this.getTblStatsGranularityDesc(tableId); + MetaStatisticsTask metaTask = new MetaStatisticsTask(jobId, + rowCountGranularity, rowCountCategory, Collections.singletonList(StatsType.ROW_COUNT)); + tasks.add(metaTask); + } else { + if (rowCount > backendIds.size() * 3700000000L) { Review Comment: got it -- This is an automated message from the Apache Git Service. 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