org.apache.iceberg.RowLevelOperationMode Maven / Gradle / Ivy
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/*
* 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.iceberg;
import org.apache.iceberg.relocated.com.google.common.base.Preconditions;
/**
* Iceberg supports two ways to modify records in a table: copy-on-write and merge-on-read.
*
* In copy-on-write, changes are materialized immediately and matching data files are replaced
* with new data files that represent the new table state. For example, if there is a record that
* has to be deleted, the data file that contains this record has to be replaced with another data
* file without that record. All unchanged rows have to be copied over to the new data file.
*
*
In merge-on-read, changes aren't materialized immediately. Instead, IDs of deleted and updated
* records are written into delete files that are applied during reads and updated/inserted records
* are written into new data files that are committed together with the delete files.
*
*
Copy-on-write changes tend to consume more time and resources during writes but don't
* introduce any performance overhead during reads. Merge-on-read operations, on the other hand,
* tend to be much faster during writes but require more time and resources to apply delete files
* during reads.
*/
public enum RowLevelOperationMode {
COPY_ON_WRITE("copy-on-write"),
MERGE_ON_READ("merge-on-read");
private final String modeName;
RowLevelOperationMode(String modeName) {
this.modeName = modeName;
}
public static RowLevelOperationMode fromName(String modeName) {
Preconditions.checkArgument(modeName != null, "Mode name is null");
if (COPY_ON_WRITE.modeName().equalsIgnoreCase(modeName)) {
return COPY_ON_WRITE;
} else if (MERGE_ON_READ.modeName().equalsIgnoreCase(modeName)) {
return MERGE_ON_READ;
} else {
throw new IllegalArgumentException("Unknown row-level operation mode: " + modeName);
}
}
public String modeName() {
return modeName;
}
}