Code review comment: 1. Imports: The added import `org.apache.commons.collections4.map.CaseInsensitiveMap` is properly placed, and the imports are correctly sorted in alphabetical order.  2. Variable Initialization: The transition from `alterClause.getProperties()` to `new CaseInsensitiveMap<>(alterClause.getProperties())` is significant. It shows an intention for case-independent key comparison, which could prevent unexpected behavior if there's inconsistency in the case of properties' keys. Although it's a minor change, documenting this would be helpful to other developers working on these parts of the code.  3. Code Separation & Readability: In the new block, containing the `try-catch` statement, you should consider adding whitespace for better readability. Further, it includes a long string concatenation operation; consider using `String.format()` for better readability and performance.     ```java    try {        DynamicPartitionUtil.checkInputDynamicPartitionProperties(properties, olapTable.getPartitionInfo());    } catch (DdlException e) {        // This table is not a dynamic partition table and didn't supply all dynamic partition properties        String errorMessage = String.format("Table %s.%s is not a dynamic partition table.",                                            db.getOriginName(), olapTable.getName());        throw new DddlException(errorMessage);    }    ```  4. No Initial Check: There appears to be no initial check whether `properties` decoded using `new CaseInsensitiveMap<>(alterClause.getProperties())` is null before trying to work with them. If `alterClause.getProperties()` can ever be `null`, the `null` would bubble up to the `CaseInsensitiveMap` constructor, potentially causing a `NullPointerException`.  5. Error Handling: While throwing a `DdlException` with a detailed error message about what happened is generally a good practice, it might be even more helpful to include the original exception as a cause of the new one, i.e., `throw new DddlException(errorMessage, e);`. This way, you do not lose the stack trace of the original exception.  6. Comment: The comment in the `catch` block—"This table is not a dynamic partition table and didn't supply all dynamic partition properties"—is meaningful, conveying why the code might reach this point. But consider moving it above the `try-catch` block to let anyone reading know what the following section is for before they start reading. Use comments to clarify "why" an operation is taking place, rather than "what" is happening.     7. Method `getAsInt()`: This method seems to be performing operations that might not be expected or suitably reflect its name based on conventional naming conventions (it manipulates data and potentially throws exceptions). It's unclear without more context, but if my inference is correct, consider refactoring this method into smaller methods with clearer responsibilities, which improve readability and maintainability. More information/context would be needed to provide exact refactor steps.

Code under review:
public AlterJobV2 analyzeAndCreateJob(List<AlterClause> alterClauses, Database db, OlapTable olapTable) throws UserException {
        
        boolean lightSchemaChange = true;
        
        IntSupplier colUniqueIdSupplier = new IntSupplier() {
            private int pendingMaxColUniqueId = olapTable.getMaxColUniqueId();

            @Override
            public int getAsInt() {
                pendingMaxColUniqueId++;
                return pendingMaxColUniqueId;
            }
        };

        
        Map<Long, LinkedList<Column>> indexSchemaMap = new HashMap<>();
        for (Map.Entry<Long, List<Column>> entry : olapTable.getIndexIdToSchema().entrySet()) {
            indexSchemaMap.put(entry.getKey(), new LinkedList<>(entry.getValue()));
        }
        List<Index> newIndexes = olapTable.getCopiedIndexes();
        Map<String, String> propertyMap = new HashMap<>();
        for (AlterClause alterClause : alterClauses) {
            Map<String, String> properties = new CaseInsensitiveMap<>(alterClause.getProperties());
            if (properties != null) {
                if (propertyMap.isEmpty()) {
                    propertyMap.putAll(properties);
                } else {
                    throw new DdlException("reduplicated PROPERTIES");
                }

                
                
                
                if (properties.containsKey(PropertyAnalyzer.PROPERTIES_COLOCATE_WITH)) {
                    String colocateGroup = properties.get(PropertyAnalyzer.PROPERTIES_COLOCATE_WITH);
                    GlobalStateMgr.getCurrentState().modifyTableColocate(db, olapTable, colocateGroup, false, null);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_DISTRIBUTION_TYPE)) {
                    GlobalStateMgr.getCurrentState().convertDistributionType(db, olapTable);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_SEND_CLEAR_ALTER_TASK)) {
                    /*
                     * This is only for fixing bug when upgrading StarRocks from 0.9.x to 0.10.x.
                     */
                    sendClearAlterTask(db, olapTable);
                    return null;
                } else if (DynamicPartitionUtil.checkDynamicPartitionPropertiesExist(properties)) {
                    if (!olapTable.dynamicPartitionExists()) {
                        try {
                            DynamicPartitionUtil
                                    .checkInputDynamicPartitionProperties(properties, olapTable.getPartitionInfo());
                        } catch (DdlException e) {
                            
                            throw new DdlException("Table " + db.getOriginName() + "." +
                                    olapTable.getName() + " is not a dynamic partition table.");
                        }
                    }
                    if (properties.containsKey(DynamicPartitionProperty.BUCKETS)) {
                        String colocateGroup = olapTable.getColocateGroup();
                        if (colocateGroup != null) {
                            throw new DdlException("The table has a colocate group:" + colocateGroup + ". so cannot " +
                                    "modify dynamic_partition.buckets. Colocate tables must have same bucket number.");
                        }
                    }
                    GlobalStateMgr.getCurrentState().modifyTableDynamicPartition(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey("default." + PropertyAnalyzer.PROPERTIES_REPLICATION_NUM)) {
                    Preconditions.checkNotNull(properties.get(PropertyAnalyzer.PROPERTIES_REPLICATION_NUM));
                    GlobalStateMgr.getCurrentState().modifyTableDefaultReplicationNum(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_REPLICATION_NUM)) {
                    GlobalStateMgr.getCurrentState().modifyTableReplicationNum(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_WRITE_QUORUM)) {
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_REPLICATED_STORAGE)) {
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_PARTITION_LIVE_NUMBER)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_STORAGE_MEDIUM)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_STORAGE_COOLDOWN_TTL)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                }
            }

            if (GlobalStateMgr.getCurrentState().getInsertOverwriteJobMgr().hasRunningOverwriteJob(olapTable.getId())) {
                
                throw new DdlException("Table[" + olapTable.getName() + "] is doing insert overwrite job, " +
                        "please start schema change after insert overwrite finished");
            }
            
            if (olapTable.existTempPartitions()) {
                throw new DdlException("Can not alter table when there are temp partitions in table");
            }

            if (alterClause instanceof AddColumnClause) {
                
                lightSchemaChange =
                        processAddColumn((AddColumnClause) alterClause, olapTable, indexSchemaMap,
                                colUniqueIdSupplier);
            } else if (alterClause instanceof AddColumnsClause) {
                
                lightSchemaChange =
                        processAddColumns((AddColumnsClause) alterClause, olapTable, indexSchemaMap, colUniqueIdSupplier);
            } else if (alterClause instanceof DropColumnClause) {
                
                lightSchemaChange =
                        processDropColumn((DropColumnClause) alterClause, olapTable, indexSchemaMap,
                                newIndexes);
            } else if (alterClause instanceof ModifyColumnClause) {
                
                processModifyColumn((ModifyColumnClause) alterClause, olapTable, indexSchemaMap);
                lightSchemaChange = false;
            } else if (alterClause instanceof ReorderColumnsClause) {
                
                lightSchemaChange = false;
                if (olapTable.getKeysType() == KeysType.PRIMARY_KEYS) {
                    List<Integer> sortKeyIdxes = new ArrayList<>();
                    List<Integer> sortKeyUniqueIds = new ArrayList<>();
                    processReorderColumnOfPrimaryKey((ReorderColumnsClause) alterClause, olapTable, indexSchemaMap, sortKeyIdxes,
                                                     sortKeyUniqueIds);
                    return createJobForProcessReorderColumnOfPrimaryKey(db.getId(), olapTable,
                            indexSchemaMap, sortKeyIdxes, sortKeyUniqueIds);
                } else {
                    processReorderColumn((ReorderColumnsClause) alterClause, olapTable, indexSchemaMap);
                }
            } else if (alterClause instanceof ModifyTablePropertiesClause) {
                
                
                lightSchemaChange = false;
            } else if (alterClause instanceof CreateIndexClause) {
                lightSchemaChange = false;
                processAddIndex((CreateIndexClause) alterClause, olapTable, newIndexes);
            } else if (alterClause instanceof DropIndexClause) {
                lightSchemaChange = false;
                processDropIndex((DropIndexClause) alterClause, olapTable, newIndexes);
            } else if (alterClause instanceof OptimizeClause) {
                return createOptimizeTableJob((OptimizeClause) alterClause, db, olapTable, propertyMap);
            } else {
                Preconditions.checkState(false);
            }
        } 

        LOG.debug("processAddColumns, table: {}({}), ligthSchemaChange: {}", olapTable.getName(), olapTable.getId(),
                lightSchemaChange);

        if (lightSchemaChange) {
            long jobId = GlobalStateMgr.getCurrentState().getNextId();
            
            modifyTableAddOrDropColumns(db, olapTable, indexSchemaMap, newIndexes, jobId, false);
            return null;
        } else {
            return createJob(db.getId(), olapTable, indexSchemaMap, propertyMap, newIndexes);
        }
    }

Line commented on: String colocateGroup = olapTable.getColocateGroup();

Revised code:
public AlterJobV2 analyzeAndCreateJob(List<AlterClause> alterClauses, Database db, OlapTable olapTable) throws UserException {
        
        boolean lightSchemaChange = true;
        
        IntSupplier colUniqueIdSupplier = new IntSupplier() {
            private int pendingMaxColUniqueId = olapTable.getMaxColUniqueId();

            @Override
            public int getAsInt() {
                pendingMaxColUniqueId++;
                return pendingMaxColUniqueId;
            }
        };

        
        Map<Long, LinkedList<Column>> indexSchemaMap = new HashMap<>();
        for (Map.Entry<Long, List<Column>> entry : olapTable.getIndexIdToSchema().entrySet()) {
            indexSchemaMap.put(entry.getKey(), new LinkedList<>(entry.getValue()));
        }
        List<Index> newIndexes = olapTable.getCopiedIndexes();
        Map<String, String> propertyMap = new HashMap<>();
        for (AlterClause alterClause : alterClauses) {
            Map<String, String> properties = alterClause.getProperties();
            if (properties != null) {
                if (propertyMap.isEmpty()) {
                    propertyMap.putAll(properties);
                } else {
                    throw new DdlException("reduplicated PROPERTIES");
                }

                
                
                
                if (properties.containsKey(PropertyAnalyzer.PROPERTIES_COLOCATE_WITH)) {
                    String colocateGroup = properties.get(PropertyAnalyzer.PROPERTIES_COLOCATE_WITH);
                    GlobalStateMgr.getCurrentState().modifyTableColocate(db, olapTable, colocateGroup, false, null);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_DISTRIBUTION_TYPE)) {
                    GlobalStateMgr.getCurrentState().convertDistributionType(db, olapTable);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_SEND_CLEAR_ALTER_TASK)) {
                    /*
                     * This is only for fixing bug when upgrading StarRocks from 0.9.x to 0.10.x.
                     */
                    sendClearAlterTask(db, olapTable);
                    return null;
                } else if (DynamicPartitionUtil.checkDynamicPartitionPropertiesExist(properties)) {
                    if (!olapTable.dynamicPartitionExists()) {
                        try {
                            DynamicPartitionUtil
                                    .checkInputDynamicPartitionProperties(properties, olapTable.getPartitionInfo());
                        } catch (DdlException e) {
                            
                            throw new DdlException("Table " + db.getOriginName() + "." +
                                    olapTable.getName() + " is not a dynamic partition table.");
                        }
                    }
                    if (properties.containsKey(DynamicPartitionProperty.BUCKETS)) {
                        String colocateGroup = olapTable.getColocateGroup();
                        if (colocateGroup != null) {
                            throw new DdlException("The table has a colocate group:" + colocateGroup + ". so cannot " +
                                    "modify dynamic_partition.buckets. Colocate tables must have same bucket number.");
                        }
                    }
                    GlobalStateMgr.getCurrentState().modifyTableDynamicPartition(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey("default." + PropertyAnalyzer.PROPERTIES_REPLICATION_NUM)) {
                    Preconditions.checkNotNull(properties.get(PropertyAnalyzer.PROPERTIES_REPLICATION_NUM));
                    GlobalStateMgr.getCurrentState().modifyTableDefaultReplicationNum(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_REPLICATION_NUM)) {
                    GlobalStateMgr.getCurrentState().modifyTableReplicationNum(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_WRITE_QUORUM)) {
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_REPLICATED_STORAGE)) {
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_PARTITION_LIVE_NUMBER)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_STORAGE_MEDIUM)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                } else if (properties.containsKey(PropertyAnalyzer.PROPERTIES_STORAGE_COOLDOWN_TTL)) {
                    GlobalStateMgr.getCurrentState().alterTableProperties(db, olapTable, properties);
                    return null;
                }
            }

            if (GlobalStateMgr.getCurrentState().getInsertOverwriteJobMgr().hasRunningOverwriteJob(olapTable.getId())) {
                
                throw new DdlException("Table[" + olapTable.getName() + "] is doing insert overwrite job, " +
                        "please start schema change after insert overwrite finished");
            }
            
            if (olapTable.existTempPartitions()) {
                throw new DdlException("Can not alter table when there are temp partitions in table");
            }

            if (alterClause instanceof AddColumnClause) {
                
                lightSchemaChange =
                        processAddColumn((AddColumnClause) alterClause, olapTable, indexSchemaMap,
                                colUniqueIdSupplier);
            } else if (alterClause instanceof AddColumnsClause) {
                
                lightSchemaChange =
                        processAddColumns((AddColumnsClause) alterClause, olapTable, indexSchemaMap, colUniqueIdSupplier);
            } else if (alterClause instanceof DropColumnClause) {
                
                lightSchemaChange =
                        processDropColumn((DropColumnClause) alterClause, olapTable, indexSchemaMap,
                                newIndexes);
            } else if (alterClause instanceof ModifyColumnClause) {
                
                processModifyColumn((ModifyColumnClause) alterClause, olapTable, indexSchemaMap);
                lightSchemaChange = false;
            } else if (alterClause instanceof ReorderColumnsClause) {
                
                lightSchemaChange = false;
                if (olapTable.getKeysType() == KeysType.PRIMARY_KEYS) {
                    List<Integer> sortKeyIdxes = new ArrayList<>();
                    List<Integer> sortKeyUniqueIds = new ArrayList<>();
                    processReorderColumnOfPrimaryKey((ReorderColumnsClause) alterClause, olapTable, indexSchemaMap, sortKeyIdxes,
                                                     sortKeyUniqueIds);
                    return createJobForProcessReorderColumnOfPrimaryKey(db.getId(), olapTable,
                            indexSchemaMap, sortKeyIdxes, sortKeyUniqueIds);
                } else {
                    processReorderColumn((ReorderColumnsClause) alterClause, olapTable, indexSchemaMap);
                }
            } else if (alterClause instanceof ModifyTablePropertiesClause) {
                
                
                lightSchemaChange = false;
            } else if (alterClause instanceof CreateIndexClause) {
                lightSchemaChange = false;
                processAddIndex((CreateIndexClause) alterClause, olapTable, newIndexes);
            } else if (alterClause instanceof DropIndexClause) {
                lightSchemaChange = false;
                processDropIndex((DropIndexClause) alterClause, olapTable, newIndexes);
            } else if (alterClause instanceof OptimizeClause) {
                return createOptimizeTableJob((OptimizeClause) alterClause, db, olapTable, propertyMap);
            } else {
                Preconditions.checkState(false);
            }
        } 

        LOG.debug("processAddColumns, table: {}({}), ligthSchemaChange: {}", olapTable.getName(), olapTable.getId(),
                lightSchemaChange);

        if (lightSchemaChange) {
            long jobId = GlobalStateMgr.getCurrentState().getNextId();
            
            modifyTableAddOrDropColumns(db, olapTable, indexSchemaMap, newIndexes, jobId, false);
            return null;
        } else {
            return createJob(db.getId(), olapTable, indexSchemaMap, propertyMap, newIndexes);
        }
    }