io.questdb.cairo.TableWriterAPI Maven / Gradle / Ivy
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*
* Copyright (c) 2014-2019 Appsicle
* Copyright (c) 2019-2023 QuestDB
*
* Licensed 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.
*
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package io.questdb.cairo;
import io.questdb.cairo.sql.TableRecordMetadata;
import io.questdb.griffin.engine.ops.AlterOperation;
import io.questdb.griffin.engine.ops.UpdateOperation;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import java.io.Closeable;
public interface TableWriterAPI extends Closeable {
default void addColumn(@NotNull CharSequence columnName, int columnType) {
addColumn(columnName, columnType, null);
}
void addColumn(@NotNull CharSequence columnName, int columnType, @Nullable SecurityContext securityContext);
/**
* Adds new column to table, which can be either empty or can have data already. When existing columns
* already have data this function will create ".top" file in addition to column files. ".top" file contains
* size of partition at the moment of column creation. It must be used to accurately position inside new
* column when either appending or reading.
*
* Failures
* Adding new column can fail in many situations. None of the failures affect integrity of data that is already in
* the table but can leave instance of TableWriter in inconsistent state. When this happens function will throw CairoError.
* Calling code must close TableWriter instance and open another when problems are rectified. Those problems would be
* either with disk or memory or both.
*
* Whenever function throws CairoException application code can continue using TableWriter instance and may attempt to
* add columns again.
*
* Transactions
*
* Pending transaction will be committed before function attempts to add column. Even when function is unsuccessful it may
* still have committed transaction.
*
* @param columnName of column either ASCII or UTF8 encoded.
* @param symbolCapacity when column columnType is SYMBOL this parameter specifies approximate capacity for symbol map.
* It should be equal to number of unique symbol values stored in the table and getting this
* value badly wrong will cause performance degradation. Must be power of 2
* @param symbolCacheFlag when set to true, symbol values will be cached on Java heap.
* @param columnType {@link ColumnType}
* @param isIndexed configures column to be indexed or not
* @param indexValueBlockCapacity approximation of number of rows for single index key, must be power of 2
* @param isSequential unused, should be false
*/
void addColumn(
CharSequence columnName,
int columnType,
int symbolCapacity,
boolean symbolCacheFlag,
boolean isIndexed,
int indexValueBlockCapacity,
boolean isSequential
);
long apply(AlterOperation alterOp, boolean contextAllowsAnyStructureChanges) throws AlterTableContextException;
long apply(UpdateOperation operation);
@Override
void close();
long commit();
TableRecordMetadata getMetadata();
/**
* Returns table structure version. Implementations must be thread-safe.
*
* @return table structure version
*/
long getMetadataVersion();
/**
* Returns safe watermark for the symbol count stored in the given column.
* The purpose of the watermark is to let ILP I/O threads (SymbolCache) to
* use symbol codes when serializing row data to be handled by the writer.
*
* If the implementation doesn't require symbol count watermarks (e.g.
* TableWriter), it should return -1.
*
* Implementations must be thread-safe.
*
* @param columnIndex column index
* @return watermark for the symbol count
*/
int getSymbolCountWatermark(int columnIndex);
TableToken getTableToken();
long getUncommittedRowCount();
/**
* Intermediate commit. It provides the best effort guarantee to commit as much data from the RSS to storage.
* However, it also takes into account O3 data overlap from the previous intermediate commits and adjust
* the internal "lag" to absorb merges while data is in RSS rather than disk.
*
* When data is in order and O3 area is empty, ic() equals to commit().
*/
void ic();
void ic(long o3MaxLag);
TableWriter.Row newRow();
TableWriter.Row newRowDeferTimestamp();
TableWriter.Row newRow(long timestamp);
void rollback();
/**
* Declares type of behaviour of the implementing class.
*
* @return true when multiple writers of this type can be used simultaneously against the same table, false otherwise.
*/
boolean supportsMultipleWriters();
/**
* Truncates non-WAL table. This method has to be called when the
* {@link CairoEngine#lockReaders(TableToken)} lock is held, i.e. when there are no readers reading from the table.
*
* @throws UnsupportedOperationException when called a WAL table.
*/
void truncate();
/**
* Truncates table, but keeps symbol tables, i.e. internal symbol string to symbol int code maps.
* Sometimes the symbols should be kept to make sure that DETACH/ATTACH PARTITION does not lose data
* for symbol columns. For non-WAL tables, this method has to be called when the
* {@link CairoEngine#lockReaders(TableToken)} lock is held, i.e. when there are no readers reading from the table.
*/
void truncateSoft();
}