[feat](nereids) disable join reorder if any table row count is not available #40349 (2.0)

fe/fe-core/src/main/java/org/apache/doris/catalog/OlapTable.java

@@ -1277,6 +1277,9 @@ public long fetchRowCount() {
         return getRowCountForIndex(baseIndexId, false);
     }
 
+    /**
+     * @return -1 if there are some tablets whose row count is not reported to FE
+     */
     public long getRowCountForIndex(long indexId, boolean strict) {
         long rowCount = 0;
         for (Map.Entry<Long, Partition> entry : idToPartition.entrySet()) {

fe/fe-core/src/main/java/org/apache/doris/nereids/NereidsPlanner.java

@@ -23,6 +23,7 @@
 import org.apache.doris.analysis.StatementBase;
 import org.apache.doris.catalog.Column;
 import org.apache.doris.catalog.Env;
+import org.apache.doris.common.FeConstants;
 import org.apache.doris.common.NereidsException;
 import org.apache.doris.common.Pair;
 import org.apache.doris.common.util.DebugUtil;
@@ -43,12 +44,14 @@
 import org.apache.doris.nereids.processor.post.PlanPostProcessors;
 import org.apache.doris.nereids.processor.pre.PlanPreprocessors;
 import org.apache.doris.nereids.properties.PhysicalProperties;
+import org.apache.doris.nereids.stats.StatsCalculator;
 import org.apache.doris.nereids.trees.expressions.Expression;
 import org.apache.doris.nereids.trees.expressions.NamedExpression;
 import org.apache.doris.nereids.trees.expressions.literal.Literal;
 import org.apache.doris.nereids.trees.plans.AbstractPlan;
 import org.apache.doris.nereids.trees.plans.Plan;
 import org.apache.doris.nereids.trees.plans.commands.ExplainCommand.ExplainLevel;
+import org.apache.doris.nereids.trees.plans.logical.LogicalOlapScan;
 import org.apache.doris.nereids.trees.plans.logical.LogicalPlan;
 import org.apache.doris.nereids.trees.plans.physical.PhysicalOneRowRelation;
 import org.apache.doris.nereids.trees.plans.physical.PhysicalPlan;
@@ -258,6 +261,16 @@ private Plan planWithoutLock(
             }
         }
 
+        // if we cannot get table row count, skip join reorder
+        // except:
+        //   1. user set leading hint
+        //   2. ut test. In ut test, FeConstants.enableInternalSchemaDb is false or FeConstants.runningUnitTest is true
+        if (FeConstants.enableInternalSchemaDb && !FeConstants.runningUnitTest && cascadesContext.isLeadingJoin()) {
+            List<LogicalOlapScan> scans = cascadesContext.getRewritePlan()
+                    .collectToList(LogicalOlapScan.class::isInstance);
+            StatsCalculator.disableJoinReorderIfTableRowCountNotAvailable(scans, cascadesContext);
+        }
+
         optimize();
         if (statementContext.getConnectContext().getExecutor() != null) {
             statementContext.getConnectContext().getExecutor().getSummaryProfile().setNereidsOptimizeTime();

fe/fe-core/src/main/java/org/apache/doris/nereids/stats/StatsCalculator.java

@@ -18,6 +18,7 @@
 package org.apache.doris.nereids.stats;
 
 import org.apache.doris.catalog.Env;
+import org.apache.doris.catalog.OlapTable;
 import org.apache.doris.catalog.TableIf;
 import org.apache.doris.common.FeConstants;
 import org.apache.doris.common.Pair;
@@ -179,6 +180,11 @@ private StatsCalculator(GroupExpression groupExpression, boolean forbidUnknownCo
         this.cascadesContext = context;
     }
 
+    private StatsCalculator(CascadesContext context) {
+        this.groupExpression = null;
+        this.cascadesContext = context;
+    }
+
     public Map<String, Histogram> getTotalHistogramMap() {
         return totalHistogramMap;
     }
@@ -1132,4 +1138,46 @@ public Statistics visitPhysicalCTEAnchor(
         return groupExpression.childStatistics(1);
     }
 
+    /**
+     * if the table is not analyzed and BE does not report row count, return -1
+     */
+    private double getOlapTableRowCount(OlapScan olapScan) {
+        OlapTable olapTable = olapScan.getTable();
+        AnalysisManager analysisManager = Env.getCurrentEnv().getAnalysisManager();
+        TableStatsMeta tableMeta = analysisManager.findTableStatsStatus(olapScan.getTable().getId());
+        double rowCount = -1;
+        if (tableMeta != null && tableMeta.userInjected) {
+            rowCount = tableMeta.getRowCount(olapScan.getSelectedIndexId());
+        } else {
+            rowCount = olapTable.getRowCountForIndex(olapScan.getSelectedIndexId(), true);
+            if (rowCount == -1) {
+                if (tableMeta != null) {
+                    rowCount = tableMeta.getRowCount(olapScan.getSelectedIndexId());
+                }
+            }
+        }
+        return rowCount;
+    }
+
+    /**
+     * disable join reorder if any table row count is not available.
+     */
+    public static void disableJoinReorderIfTableRowCountNotAvailable(
+            List<LogicalOlapScan> scans,
+            CascadesContext context) {
+        StatsCalculator calculator = new StatsCalculator(context);
+        for (LogicalOlapScan scan : scans) {
+            double rowCount = calculator.getOlapTableRowCount(scan);
+            if (rowCount == -1 && ConnectContext.get() != null) {
+                try {
+                    ConnectContext.get().getSessionVariable().disableNereidsJoinReorderOnce();
+                    LOG.info("disable join reorder since row count not available: "
+                            + scan.getTable().getNameWithFullQualifiers());
+                } catch (Exception e) {
+                    LOG.info("disableNereidsJoinReorderOnce failed");
+                }
+                return;
+            }
+        }
+    }
 }