[Fix](statistics)Need to recalculate health value when table row count become 0 (#27673)

Need to recalculate health value when table row count become 0. Otherwise, when user truncate a table, the old statistics will not be updated.

fe/fe-core/src/main/java/org/apache/doris/statistics/AnalysisManager.java

@@ -724,6 +724,21 @@ public class AnalysisManager implements Writable {
         StatisticsRepository.dropStatistics(tblId, cols);
     }
 
+    public void dropStats(TableIf table) throws DdlException {
+        TableStatsMeta tableStats = findTableStatsStatus(table.getId());
+        if (tableStats == null) {
+            return;
+        }
+        Set<String> cols = table.getBaseSchema().stream().map(Column::getName).collect(Collectors.toSet());
+        for (String col : cols) {
+            tableStats.removeColumn(col);
+            Env.getCurrentEnv().getStatisticsCache().invalidate(table.getId(), -1L, col);
+        }
+        tableStats.updatedTime = 0;
+        logCreateTableStats(tableStats);
+        StatisticsRepository.dropStatistics(table.getId(), cols);
+    }
+
     public void handleKillAnalyzeStmt(KillAnalysisJobStmt killAnalysisJobStmt) throws DdlException {
         Map<Long, BaseAnalysisTask> analysisTaskMap = analysisJobIdToTaskMap.remove(killAnalysisJobStmt.jobId);
         if (analysisTaskMap == null) {

fe/fe-core/src/main/java/org/apache/doris/statistics/StatisticsAutoCollector.java

@@ -91,15 +91,21 @@ public class StatisticsAutoCollector extends StatisticsCollector {
     public void analyzeDb(DatabaseIf<TableIf> databaseIf) throws DdlException {
         List<AnalysisInfo> analysisInfos = constructAnalysisInfo(databaseIf);
         for (AnalysisInfo analysisInfo : analysisInfos) {
-            analysisInfo = getReAnalyzeRequiredPart(analysisInfo);
-            if (analysisInfo == null) {
-                continue;
-            }
             try {
+                if (needDropStaleStats(analysisInfo)) {
+                    Env.getCurrentEnv().getAnalysisManager().dropStats(databaseIf.getTable(analysisInfo.tblId).get());
+                    continue;
+                }
+                analysisInfo = getReAnalyzeRequiredPart(analysisInfo);
+                if (analysisInfo == null) {
+                    continue;
+                }
                 createSystemAnalysisJob(analysisInfo);
             } catch (Throwable t) {
                 analysisInfo.message = t.getMessage();
-                throw t;
+                LOG.warn("Failed to auto analyze table {}.{}, reason {}",
+                        databaseIf.getFullName(), analysisInfo.tblId, analysisInfo.message, t);
+                continue;
             }
         }
     }
@@ -191,4 +197,29 @@ public class StatisticsAutoCollector extends StatisticsCollector {
         return new AnalysisInfoBuilder(jobInfo).setColToPartitions(needRunPartitions).build();
     }
 
+    /**
+     * Check if the given table should drop stale stats. User may truncate table,
+     * in this case, we need to drop the stale stats.
+     * @param jobInfo
+     * @return True if you need to drop, false otherwise.
+     */
+    protected boolean needDropStaleStats(AnalysisInfo jobInfo) {
+        TableIf table = StatisticsUtil
+                .findTable(jobInfo.catalogId, jobInfo.dbId, jobInfo.tblId);
+        if (!(table instanceof OlapTable)) {
+            return false;
+        }
+        AnalysisManager analysisManager = Env.getServingEnv().getAnalysisManager();
+        TableStatsMeta tblStats = analysisManager.findTableStatsStatus(table.getId());
+        if (tblStats == null) {
+            return false;
+        }
+        if (tblStats.analyzeColumns().isEmpty()) {
+            return false;
+        }
+        if (table.getRowCount() == 0) {
+            return true;
+        }
+        return false;
+    }
 }

fe/fe-core/src/main/java/org/apache/doris/statistics/util/StatisticsUtil.java

@@ -522,8 +522,7 @@ public class StatisticsUtil {
      *
      * @param updatedRows The number of rows updated by the table
      * @param totalRows The current number of rows in the table
-     *         the healthier the statistics of the table
-     * @return Health, the value range is [0, 100], the larger the value,
+     * @return Health, the value range is [0, 100], the larger the value, the healthier the statistics of the table.
      */
     public static int getTableHealth(long totalRows, long updatedRows) {
         if (updatedRows >= totalRows) {