[improvement](statistics)Use real base index id to fetch stats cache.

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

@@ -350,7 +350,7 @@ private void adjustColStats(CatalogRelation catalogRelation, SlotReference slot,
     private ColumnStatistic getColumnStatsFromTableCache(CatalogRelation catalogRelation, SlotReference slot) {
         long idxId = -1;
         if (catalogRelation instanceof OlapScan) {
-            idxId = ((OlapScan) catalogRelation).getSelectedIndexIdForMV();
+            idxId = ((OlapScan) catalogRelation).getSelectedIndexId();
         }
         return getColumnStatistic(catalogRelation.getTable(), slot.getName(), idxId);
     }
@@ -359,7 +359,7 @@ private ColumnStatistic getColumnStatsFromPartitionCache(CatalogRelation catalog
             List<String> partitionNames) {
         long idxId = -1;
         if (catalogRelation instanceof OlapScan) {
-            idxId = ((OlapScan) catalogRelation).getSelectedIndexIdForMV();
+            idxId = ((OlapScan) catalogRelation).getSelectedIndexId();
         }
         return getColumnStatistic(catalogRelation.getTable(), slot.getName(), idxId, partitionNames);
     }
@@ -434,7 +434,7 @@ private Statistics computeOlapScan(LogicalOlapScan olapScan) {
             for (Slot slot : olapScan.getOutput()) {
                 if (isVisibleSlotReference(slot)) {
                     ColumnStatistic cache = getColumnStatistic(olapTable, slot.getName(),
-                            olapScan.getSelectedIndexIdForMV());
+                            olapScan.getSelectedIndexId());
                     rowCount = Math.max(rowCount, cache.count);
                 }
                 builder.putColumnStatistics(slot,

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/algebra/OlapScan.java

@@ -28,12 +28,6 @@ public interface OlapScan {
 
     long getSelectedIndexId();
 
-    /**
-     * if this is mv, return selectedIndexId, o.w -1
-     * @return -1 or selectedIndexId
-     */
-    long getSelectedIndexIdForMV();
-
     List<Long> getSelectedPartitionIds();
 
     List<Long> getSelectedTabletIds();

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/logical/LogicalDeferMaterializeOlapScan.java

@@ -93,11 +93,6 @@ public long getSelectedIndexId() {
         return logicalOlapScan.getSelectedIndexId();
     }
 
-    @Override
-    public long getSelectedIndexIdForMV() {
-        return logicalOlapScan.getSelectedIndexIdForMV();
-    }
-
     @Override
     public List<Long> getSelectedPartitionIds() {
         return logicalOlapScan.getSelectedPartitionIds();

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/logical/LogicalOlapScan.java

@@ -333,14 +333,6 @@ public long getSelectedIndexId() {
         return selectedIndexId;
     }
 
-    @Override
-    public long getSelectedIndexIdForMV() {
-        if (getTable().getBaseIndexId() != selectedIndexId) {
-            return selectedIndexId;
-        }
-        return -1;
-    }
-
     public boolean isIndexSelected() {
         return indexSelected;
     }

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/physical/PhysicalDeferMaterializeOlapScan.java

@@ -90,11 +90,6 @@ public long getSelectedIndexId() {
         return physicalOlapScan.getSelectedIndexId();
     }
 
-    @Override
-    public long getSelectedIndexIdForMV() {
-        return physicalOlapScan.getSelectedIndexIdForMV();
-    }
-
     @Override
     public List<Long> getSelectedPartitionIds() {
         return physicalOlapScan.getSelectedPartitionIds();

fe/fe-core/src/main/java/org/apache/doris/nereids/trees/plans/physical/PhysicalOlapScan.java

@@ -90,14 +90,6 @@ public long getSelectedIndexId() {
         return selectedIndexId;
     }
 
-    @Override
-    public long getSelectedIndexIdForMV() {
-        if (getTable().getBaseIndexId() != selectedIndexId) {
-            return selectedIndexId;
-        }
-        return -1;
-    }
-
     @Override
     public List<Long> getSelectedTabletIds() {
         return selectedTabletIds;

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

@@ -18,6 +18,8 @@
 package org.apache.doris.statistics;
 
 import org.apache.doris.catalog.Env;
+import org.apache.doris.catalog.OlapTable;
+import org.apache.doris.catalog.TableIf;
 import org.apache.doris.common.ClientPool;
 import org.apache.doris.common.Config;
 import org.apache.doris.common.FeConstants;
@@ -91,6 +93,12 @@ public ColumnStatistic getColumnStatistics(long catalogId, long dbId, long tblId
         if (ctx != null && ctx.getSessionVariable().internalSession) {
             return ColumnStatistic.UNKNOWN;
         }
+        // Need to change base index id to -1 for OlapTable.
+        try {
+            idxId = changeBaseIndexId(catalogId, dbId, tblId, idxId);
+        } catch (Exception e) {
+            return ColumnStatistic.UNKNOWN;
+        }
         StatisticsCacheKey k = new StatisticsCacheKey(catalogId, dbId, tblId, idxId, colName);
         try {
             CompletableFuture<Optional<ColumnStatistic>> f = columnStatisticsCache.get(k);
@@ -109,6 +117,12 @@ public PartitionColumnStatistic getPartitionColumnStatistics(long catalogId, lon
         if (ctx != null && ctx.getSessionVariable().internalSession) {
             return PartitionColumnStatistic.UNKNOWN;
         }
+        // Need to change base index id to -1 for OlapTable.
+        try {
+            idxId = changeBaseIndexId(catalogId, dbId, tblId, idxId);
+        } catch (Exception e) {
+            return PartitionColumnStatistic.UNKNOWN;
+        }
         PartitionColumnStatisticCacheKey k = new PartitionColumnStatisticCacheKey(
                 catalogId, dbId, tblId, idxId, partName, colName);
         try {
@@ -122,6 +136,21 @@ public PartitionColumnStatistic getPartitionColumnStatistics(long catalogId, lon
         return PartitionColumnStatistic.UNKNOWN;
     }
 
+    // Base index id should be set to -1 for OlapTable. Because statistics tables use -1 for base index.
+    // TODO: Need to use the real index id in statistics table in later version.
+    private long changeBaseIndexId(long catalogId, long dbId, long tblId, long idxId) {
+        if (idxId != -1) {
+            TableIf table = StatisticsUtil.findTable(catalogId, dbId, tblId);
+            if (table instanceof OlapTable) {
+                OlapTable olapTable = (OlapTable) table;
+                if (idxId == olapTable.getBaseIndexId()) {
+                    idxId = -1;
+                }
+            }
+        }
+        return idxId;
+    }
+
     public Histogram getHistogram(long ctlId, long dbId, long tblId, String colName) {
         return getHistogram(ctlId, dbId, tblId, -1, colName).orElse(null);
     }