org.forstdb.PrepopulateBlobCache Maven / Gradle / Ivy
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// Copyright (c) Meta Platforms, Inc. and affiliates.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
package org.forstdb;
/**
* Enum PrepopulateBlobCache
*
* Prepopulate warm/hot blobs which are already in memory into blob
* cache at the time of flush. On a flush, the blob that is in memory
* (in memtables) get flushed to the device. If using Direct IO,
* additional IO is incurred to read this blob back into memory again,
* which is avoided by enabling this option. This further helps if the
* workload exhibits high temporal locality, where most of the reads go
* to recently written data. This also helps in case of the remote file
* system since it involves network traffic and higher latencies.
*/
public enum PrepopulateBlobCache {
PREPOPULATE_BLOB_DISABLE((byte) 0x0, "prepopulate_blob_disable", "kDisable"),
PREPOPULATE_BLOB_FLUSH_ONLY((byte) 0x1, "prepopulate_blob_flush_only", "kFlushOnly");
/**
* Get the PrepopulateBlobCache enumeration value by
* passing the library name to this method.
*
* If library cannot be found the enumeration
* value {@code PREPOPULATE_BLOB_DISABLE} will be returned.
*
* @param libraryName prepopulate blob cache library name.
*
* @return PrepopulateBlobCache instance.
*/
public static PrepopulateBlobCache getPrepopulateBlobCache(String libraryName) {
if (libraryName != null) {
for (PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
if (prepopulateBlobCache.getLibraryName() != null
&& prepopulateBlobCache.getLibraryName().equals(libraryName)) {
return prepopulateBlobCache;
}
}
}
return PrepopulateBlobCache.PREPOPULATE_BLOB_DISABLE;
}
/**
* Get the PrepopulateBlobCache enumeration value by
* passing the byte identifier to this method.
*
* @param byteIdentifier of PrepopulateBlobCache.
*
* @return PrepopulateBlobCache instance.
*
* @throws IllegalArgumentException If PrepopulateBlobCache cannot be found for the
* provided byteIdentifier
*/
public static PrepopulateBlobCache getPrepopulateBlobCache(byte byteIdentifier) {
for (final PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
if (prepopulateBlobCache.getValue() == byteIdentifier) {
return prepopulateBlobCache;
}
}
throw new IllegalArgumentException("Illegal value provided for PrepopulateBlobCache.");
}
/**
* Get a PrepopulateBlobCache value based on the string key in the C++ options output.
* This gets used in support of getting options into Java from an options string,
* which is generated at the C++ level.
*
*
* @param internalName the internal (C++) name by which the option is known.
*
* @return PrepopulateBlobCache instance (optional)
*/
static PrepopulateBlobCache getFromInternal(final String internalName) {
for (final PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
if (prepopulateBlobCache.internalName_.equals(internalName)) {
return prepopulateBlobCache;
}
}
throw new IllegalArgumentException(
"Illegal internalName '" + internalName + " ' provided for PrepopulateBlobCache.");
}
/**
* Returns the byte value of the enumerations value.
*
* @return byte representation
*/
public byte getValue() {
return value_;
}
/**
* Returns the library name of the prepopulate blob cache mode
* identified by the enumeration value.
*
* @return library name
*/
public String getLibraryName() {
return libraryName_;
}
PrepopulateBlobCache(final byte value, final String libraryName, final String internalName) {
value_ = value;
libraryName_ = libraryName;
internalName_ = internalName;
}
private final byte value_;
private final String libraryName_;
private final String internalName_;
}