Page Comparison

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1. Operations
   1. Perform single + batch read on single + multiple dataset from script transform
   2. Perform single + batch read on DistributedCache single + multiple files from script transform
2. Supported datasets tables for lookup
   1. Key-value table
   2. ObjectMappedTableKeyValueTable dataset
   3. ObjectMappedTable dataset
   4. CSV files treated as a list of key-value pairs
3. Optional caching with time-based expiration

Design

1. LookupKV  Lookup interface 

   Code Block
   Objectinterface Lookup<T> { T lookup(String key); Map<String, Object>T> multiLookup(String[] key);

   Implement LookupKV

   lookup(String... keys); Map<String, T> lookup(Set<String> keys); }

2. Implement Lookup in KeyValueTable and ObjectMappedTable
   1. KeyValueTable implements Lookup<String>
   2. ObjectMappedTable implements Lookup<StructuredRecord>
3. DatasetConfigurer changes
   1. Add method: void useDataset(String datasetName);
4. ScriptTransform changes

   1. Add configuration property for declaring lookup tables to use, properties for each table (e.g. dataset properties)

      Example

      Code Block
      "tables": [ { "name":"purchases", "type":"dataset", "properties": { "dataset":"purchases",

      "datasetProperties": {

      "properties":{.. dataset properties ..}, "

      enable.cache

      enableCache":"true", "

      cache.expiry

      cacheExpiry":1234 } }, {"name":"ip2geo", "type":"file", "properties":{"file":"/data/ip2geo.csv"}} ]

   2. configure(): verify datasets / tables existtables (datasets and files) exist by calling DatasetConfigurer.useDataset()
   3. transform(): execute lookup methods in a transaction, provide LookupKV Lookup instance to script
      1. Sample

         Options for lookup usage: 

         Code Block
         var result = context.

         getTable

         getLookup("purchases").lookup(user)

      2. Alternative: tables["purchases"].lookup(user)
      3. Alternative: purchases.lookup(user)
      4. Sample usage for multiLookup

         ;

      5. Options for batch lookup usage:

         Code Block
         var result = context.getLookup("purchases").multiLookuplookup(["alice", "bob"]); // do something with result["alice"] // do something with result["bob"]

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