ceph/src/rocksdb/java/src/main/java/org/rocksdb/PrepopulateBlobCache.java

   1 //  Copyright (c) Meta Platforms, Inc. and affiliates.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 package org.rocksdb;
   7
   8 /**
   9  * Enum PrepopulateBlobCache
  10  *
  11  * <p>Prepopulate warm/hot blobs which are already in memory into blob
  12  * cache at the time of flush. On a flush, the blob that is in memory
  13  * (in memtables) get flushed to the device. If using Direct IO,
  14  * additional IO is incurred to read this blob back into memory again,
  15  * which is avoided by enabling this option. This further helps if the
  16  * workload exhibits high temporal locality, where most of the reads go
  17  * to recently written data. This also helps in case of the remote file
  18  * system since it involves network traffic and higher latencies.</p>
  19  */
  20 public enum PrepopulateBlobCache {
  21   PREPOPULATE_BLOB_DISABLE((byte) 0x0, "prepopulate_blob_disable", "kDisable"),
  22   PREPOPULATE_BLOB_FLUSH_ONLY((byte) 0x1, "prepopulate_blob_flush_only", "kFlushOnly");
  23
  24   /**
  25    * <p>Get the PrepopulateBlobCache enumeration value by
  26    * passing the library name to this method.</p>
  27    *
  28    * <p>If library cannot be found the enumeration
  29    * value {@code PREPOPULATE_BLOB_DISABLE} will be returned.</p>
  30    *
  31    * @param libraryName prepopulate blob cache library name.
  32    *
  33    * @return PrepopulateBlobCache instance.
  34    */
  35   public static PrepopulateBlobCache getPrepopulateBlobCache(String libraryName) {
  36     if (libraryName != null) {
  37       for (PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
  38         if (prepopulateBlobCache.getLibraryName() != null
  39             && prepopulateBlobCache.getLibraryName().equals(libraryName)) {
  40           return prepopulateBlobCache;
  41         }
  42       }
  43     }
  44     return PrepopulateBlobCache.PREPOPULATE_BLOB_DISABLE;
  45   }
  46
  47   /**
  48    * <p>Get the PrepopulateBlobCache enumeration value by
  49    * passing the byte identifier to this method.</p>
  50    *
  51    * @param byteIdentifier of PrepopulateBlobCache.
  52    *
  53    * @return PrepopulateBlobCache instance.
  54    *
  55    * @throws IllegalArgumentException If PrepopulateBlobCache cannot be found for the
  56    *   provided byteIdentifier
  57    */
  58   public static PrepopulateBlobCache getPrepopulateBlobCache(byte byteIdentifier) {
  59     for (final PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
  60       if (prepopulateBlobCache.getValue() == byteIdentifier) {
  61         return prepopulateBlobCache;
  62       }
  63     }
  64
  65     throw new IllegalArgumentException("Illegal value provided for PrepopulateBlobCache.");
  66   }
  67
  68   /**
  69    * <p>Get a PrepopulateBlobCache value based on the string key in the C++ options output.
  70    * This gets used in support of getting options into Java from an options string,
  71    * which is generated at the C++ level.
  72    * </p>
  73    *
  74    * @param internalName the internal (C++) name by which the option is known.
  75    *
  76    * @return PrepopulateBlobCache instance (optional)
  77    */
  78   static PrepopulateBlobCache getFromInternal(final String internalName) {
  79     for (final PrepopulateBlobCache prepopulateBlobCache : PrepopulateBlobCache.values()) {
  80       if (prepopulateBlobCache.internalName_.equals(internalName)) {
  81         return prepopulateBlobCache;
  82       }
  83     }
  84
  85     throw new IllegalArgumentException(
  86         "Illegal internalName '" + internalName + " ' provided for PrepopulateBlobCache.");
  87   }
  88
  89   /**
  90    * <p>Returns the byte value of the enumerations value.</p>
  91    *
  92    * @return byte representation
  93    */
  94   public byte getValue() {
  95     return value_;
  96   }
  97
  98   /**
  99    * <p>Returns the library name of the prepopulate blob cache mode
 100    * identified by the enumeration value.</p>
 101    *
 102    * @return library name
 103    */
 104   public String getLibraryName() {
 105     return libraryName_;
 106   }
 107
 108   PrepopulateBlobCache(final byte value, final String libraryName, final String internalName) {
 109     value_ = value;
 110     libraryName_ = libraryName;
 111     internalName_ = internalName;
 112   }
 113
 114   private final byte value_;
 115   private final String libraryName_;
 116   private final String internalName_;
 117 }