[fix](nereids)mv selection should rule out shadow index from schema c…

…hange (#37154)

schema change would introduce a shadow index. MV selection should rule
out the shadow index.

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

@@ -2990,4 +2990,13 @@ public long getRemoteDataSize() {
     public long getReplicaCount() {
         return statistics.getReplicaCount();
     }
+
+    public boolean isShadowIndex(long indexId) {
+        String indexName = getIndexNameById(indexId);
+        if (indexName != null && indexName.startsWith(org.apache.doris.alter.SchemaChangeHandler.SHADOW_NAME_PREFIX)) {
+            return true;
+        } else {
+            return false;
+        }
+    }
 }

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/exploration/mv/InitMaterializationContextHook.java

@@ -145,7 +145,10 @@ private List<SyncMaterializationContext> createSyncMvContexts(OlapTable olapTabl
             keyCount += column.isKey() ? 1 : 0;
         }
         for (Map.Entry<String, Long> entry : olapTable.getIndexNameToId().entrySet()) {
-            if (entry.getValue() != baseIndexId) {
+            long indexId = entry.getValue();
+            // when doing schema change, a shadow index would be created and put together with mv indexes
+            // we must roll out these unexpected shadow indexes here
+            if (indexId != baseIndexId && !olapTable.isShadowIndex(indexId)) {
                 MaterializedIndexMeta meta = olapTable.getIndexMetaByIndexId(entry.getValue());
                 String createMvSql;
                 if (meta.getDefineStmt() != null) {