virajjasani commented on code in PR #2209: URL: https://github.com/apache/phoenix/pull/2209#discussion_r2188078156
########## phoenix-core-server/src/main/java/org/apache/phoenix/coprocessor/CDCCompactionUtil.java: ########## @@ -0,0 +1,395 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.phoenix.coprocessor; + +import org.apache.hadoop.hbase.Cell; +import org.apache.hadoop.hbase.CellUtil; +import org.apache.hadoop.hbase.TableName; +import org.apache.hadoop.hbase.client.CheckAndMutate; +import org.apache.hadoop.hbase.client.CheckAndMutateResult; +import org.apache.hadoop.hbase.client.Get; +import org.apache.hadoop.hbase.client.Put; +import org.apache.hadoop.hbase.client.Result; +import org.apache.hadoop.hbase.client.Table; +import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment; +import org.apache.hadoop.hbase.regionserver.Region; +import org.apache.hadoop.hbase.util.Bytes; +import org.apache.phoenix.expression.function.PartitionIdFunction; +import org.apache.phoenix.hbase.index.ValueGetter; +import org.apache.phoenix.hbase.index.util.GenericKeyValueBuilder; +import org.apache.phoenix.hbase.index.util.ImmutableBytesPtr; +import org.apache.phoenix.index.IndexMaintainer; +import org.apache.phoenix.jdbc.PhoenixConnection; +import org.apache.phoenix.query.QueryConstants; +import org.apache.phoenix.schema.PColumn; +import org.apache.phoenix.schema.PTable; +import org.apache.phoenix.schema.types.PDate; +import org.apache.phoenix.util.CDCUtil; +import org.apache.phoenix.util.IndexUtil; +import org.apache.phoenix.util.JacksonUtil; +import org.apache.phoenix.util.QueryUtil; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.Map; +import java.util.Properties; + +import static org.apache.phoenix.query.QueryConstants.NAME_SEPARATOR; + +/** + * Utility class for CDC (Change Data Capture) operations during compaction. + * This class contains utilities for handling TTL row expiration events and generating + * CDC events with pre-image data that are written directly to CDC index tables. + */ +public final class CDCCompactionUtil { + + private static final Logger LOGGER = LoggerFactory.getLogger(CDCCompactionUtil.class); + + private CDCCompactionUtil() { + // empty + } + + /** + * Finds the column name for a given cell in the data table. + * + * @param dataTable The data table + * @param cell The cell + * @return The column name or null if not found + */ + static String findColumnName(PTable dataTable, Cell cell) { + try { + byte[] family = CellUtil.cloneFamily(cell); + byte[] qualifier = CellUtil.cloneQualifier(cell); + byte[] defaultCf = dataTable.getDefaultFamilyName() != null + ? dataTable.getDefaultFamilyName().getBytes() + : QueryConstants.DEFAULT_COLUMN_FAMILY_BYTES; + for (PColumn column : dataTable.getColumns()) { + if (column.getFamilyName() != null + && Bytes.equals(family, column.getFamilyName().getBytes()) + && Bytes.equals(qualifier, column.getColumnQualifierBytes())) { + if (Bytes.equals(defaultCf, column.getFamilyName().getBytes())) { + return column.getName().getString(); + } else { + return column.getFamilyName().getString() + NAME_SEPARATOR + + column.getName().getString(); + } + } + } + } catch (Exception e) { + LOGGER.error("Error finding column name for cell: {}", CellUtil.toString(cell, true), + e); + } + return null; + } + + /** + * Creates a CDC event map for TTL delete with pre-image data. + * + * @param expiredRowPut The expired row data + * @param dataTable The data table + * @param preImage Pre-image map + * @return CDC event map + */ + static Map<String, Object> createTTLDeleteCDCEvent(Put expiredRowPut, PTable dataTable, + Map<String, Object> preImage) + throws Exception { + Map<String, Object> cdcEvent = new HashMap<>(); + cdcEvent.put(QueryConstants.CDC_EVENT_TYPE, QueryConstants.CDC_TTL_DELETE_EVENT_TYPE); + for (List<Cell> familyCells : expiredRowPut.getFamilyCellMap().values()) { + for (Cell cell : familyCells) { + String columnName = findColumnName(dataTable, cell); + if (columnName != null) { + PColumn column = dataTable.getColumnForColumnQualifier( + CellUtil.cloneFamily(cell), CellUtil.cloneQualifier(cell)); + Object value = column.getDataType().toObject(cell.getValueArray(), + cell.getValueOffset(), + cell.getValueLength()); + Object encodedValue = + CDCUtil.getColumnEncodedValue(value, column.getDataType()); + preImage.put(columnName, encodedValue); + } + } + } + cdcEvent.put(QueryConstants.CDC_PRE_IMAGE, preImage); + cdcEvent.put(QueryConstants.CDC_POST_IMAGE, Collections.emptyMap()); + return cdcEvent; + } + + /** + * Builds CDC index Put mutation. + * + * @param cdcIndex The CDC index table + * @param expiredRowPut The expired row data as a Put + * @param eventTimestamp The timestamp for the CDC event + * @param cdcEventBytes The CDC event data to store + * @param dataTable The data table + * @param env The region coprocessor environment + * @param region The HBase region + * @param compactionTimeBytes The compaction time as bytes + * @return The CDC index Put mutation + */ + static Put buildCDCIndexPut(PTable cdcIndex, Put expiredRowPut, long eventTimestamp, + byte[] cdcEventBytes, PTable dataTable, + RegionCoprocessorEnvironment env, Region region, + byte[] compactionTimeBytes) throws Exception { + + try (PhoenixConnection serverConnection = QueryUtil.getConnectionOnServer(new Properties(), + env.getConfiguration()).unwrap(PhoenixConnection.class)) { + + IndexMaintainer cdcIndexMaintainer = + cdcIndex.getIndexMaintainer(dataTable, serverConnection); + + ValueGetter dataRowVG = new IndexUtil.SimpleValueGetter(expiredRowPut); + ImmutableBytesPtr rowKeyPtr = new ImmutableBytesPtr(expiredRowPut.getRow()); + + Put cdcIndexPut = cdcIndexMaintainer.buildUpdateMutation( + GenericKeyValueBuilder.INSTANCE, + dataRowVG, + rowKeyPtr, + eventTimestamp, + null, + null, + false, + region.getRegionInfo().getEncodedNameAsBytes()); + + byte[] rowKey = cdcIndexPut.getRow().clone(); + System.arraycopy(compactionTimeBytes, 0, rowKey, + PartitionIdFunction.PARTITION_ID_LENGTH, PDate.INSTANCE.getByteSize()); + Put newCdcIndexPut = new Put(rowKey, eventTimestamp); + + newCdcIndexPut.addColumn( + cdcIndexMaintainer.getEmptyKeyValueFamily().copyBytesIfNecessary(), + cdcIndexMaintainer.getEmptyKeyValueQualifier(), eventTimestamp, + QueryConstants.UNVERIFIED_BYTES); + + // Add CDC event data + newCdcIndexPut.addColumn( + QueryConstants.DEFAULT_COLUMN_FAMILY_BYTES, + QueryConstants.CDC_IMAGE_CQ_BYTES, + eventTimestamp, + cdcEventBytes); + + return newCdcIndexPut; + } + } + + /** + * Generates and applies a CDC index mutation for TTL expired row with retries if required. + * + * @param cdcIndex The CDC index table + * @param dataTable The data table + * @param expiredRowPut The expired row data as a Put + * @param eventTimestamp The timestamp for the CDC event + * @param tableName The table name for logging + * @param env The region coprocessor environment + * @param region The HBase region + * @param compactionTimeBytes The compaction time as bytes + * @param cdcTtlMutationMaxRetries Maximum retry attempts for CDC mutations + */ + static void generateCDCIndexMutation(PTable cdcIndex, PTable dataTable, + Put expiredRowPut, + long eventTimestamp, String tableName, + RegionCoprocessorEnvironment env, Region region, + byte[] compactionTimeBytes, + int cdcTtlMutationMaxRetries) + throws Exception { + Map<String, Object> cdcEvent = + createTTLDeleteCDCEvent(expiredRowPut, dataTable, new HashMap<>()); + byte[] cdcEventBytes = + JacksonUtil.getObjectWriter(HashMap.class).writeValueAsBytes(cdcEvent); + Put cdcIndexPut = + buildCDCIndexPut(cdcIndex, expiredRowPut, eventTimestamp, cdcEventBytes, + dataTable, env, region, compactionTimeBytes); + + Exception lastException = null; + for (int retryCount = 0; retryCount < cdcTtlMutationMaxRetries; retryCount++) { + try (Table cdcIndexTable = env.getConnection().getTable(TableName.valueOf( + cdcIndex.getPhysicalName().getBytes()))) { + CheckAndMutate checkAndMutate = + CheckAndMutate.newBuilder(cdcIndexPut.getRow()) + .ifNotExists(QueryConstants.DEFAULT_COLUMN_FAMILY_BYTES, + QueryConstants.CDC_IMAGE_CQ_BYTES) + .build(cdcIndexPut); + CheckAndMutateResult result = cdcIndexTable.checkAndMutate(checkAndMutate); + + if (result.isSuccess()) { + // Successfully inserted new CDC event - Single CF case + lastException = null; + break; + } else { + // Row already exists, need to retrieve existing pre-image and merge + // Likely to happen for multi CF case + Get get = new Get(cdcIndexPut.getRow()); + get.addColumn(QueryConstants.DEFAULT_COLUMN_FAMILY_BYTES, + QueryConstants.CDC_IMAGE_CQ_BYTES); + Result existingResult = cdcIndexTable.get(get); + + if (!existingResult.isEmpty()) { + Cell existingCell = existingResult.getColumnLatestCell( + QueryConstants.DEFAULT_COLUMN_FAMILY_BYTES, + QueryConstants.CDC_IMAGE_CQ_BYTES); + + if (existingCell != null) { + byte[] existingCdcBytes = CellUtil.cloneValue(existingCell); + Map<String, Object> existingCdcEvent = + JacksonUtil.getObjectReader(HashMap.class) + .readValue(existingCdcBytes); + Map<String, Object> existingPreImage = + (Map<String, Object>) existingCdcEvent.getOrDefault( + QueryConstants.CDC_PRE_IMAGE, new HashMap<>()); + + // Create new TTL delete event with merged pre-image + Map<String, Object> mergedCdcEvent = + createTTLDeleteCDCEvent(expiredRowPut, dataTable, + existingPreImage); + byte[] mergedCdcEventBytes = + JacksonUtil.getObjectWriter(HashMap.class) + .writeValueAsBytes(mergedCdcEvent); + + Put mergedCdcIndexPut = buildCDCIndexPut(cdcIndex, expiredRowPut, + eventTimestamp, mergedCdcEventBytes, dataTable, env, region, + compactionTimeBytes); Review Comment: This was the initial idea we discussed but providing the in-built image seems far more efficient because the same change event can be consumed multiple times (by multiple consumers). When that happens, we will keep deserializing cells on the fly, rather than let the compaction take care of deserializing to the exact bytes that the scanner will return without any additional logic. This approach seemed more efficient in the case where we need to provide pre-built image. In other normal cases (upsert and delete), since we are scanning the data table, there is anyways no scope for bringing extra efficiency in compute while scanning and forming "CDC JSON" column cell. However, here we can make it much simpler: let compaction write the change image, whereas scanner can read it multiple times without any additional compute. To sum up, when we need to scan the data table, we anyways deal with multi-CF. However, when we need to provide pre-built image, using single CF (default CF) is better so that read becomes simpler. -- This is an automated message from the Apache Git Service. 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