Session: Patch Time Series

• To patch time series entries to a document, use session.Advanced.Defer.

  • You can pass Defer a script to Append, Get, and Remove time series entries.
  • You can handle a single document at a time.

• Patching Using session.Advanced.Defer

  • Syntax
  • Usage Flow
  • Usage Samples

Patching Using session.Advanced.Defer

• Defer is used for patching in general, not necessarily for time series data patching.
• To patch time series data, you need to customize the JavaScript that Defer uses.
• Learn more about time series JavaScript here.

Syntax

• PatchCommandData
  • Definition

public PatchCommandData(string id, string changeVector,
  PatchRequest patch, PatchRequest patchIfMissing)

Learn more about PatchCommandData here.

• PatchRequest
  • Definition

public class PatchRequest
{
  // The patching script     
  public string Script { get; set; }
  
  // Values for the parameters used by the patching script
  public Dictionary<string, object> Values { get; set; }
}

Learn more about PatchRequest here.

Usage Flow

• Open a session
• Call session.Advanced.Defer and pass it a PatchCommandData instance.
• Pass the PatchCommandData constructor method -
  • the document ID
  • the change vector (or null)
  • a PatchRequest instance with a JavaScript that appends or removes time series entries.
• Call session.SaveChanges() to perform the patch.

Usage Samples

• In this sample, we pass Defer a script that appends a document 100 time series entries with random heart rate values.

var baseline = DateTime.Today;

// Create arrays of timestamps and random values to patch
List<double> values = new List<double>();
List<DateTime> timeStamps = new List<DateTime>();

for (var i = 0; i < 100; i++)
{
  values.Add(68 + Math.Round(19 * new Random().NextDouble()));
  timeStamps.Add(baseline.AddSeconds(i));
}

session.Advanced.Defer(new PatchCommandData("users/1-A", null,
  new PatchRequest
  {
      Script = @"
          var i = 0;
          for(i = 0; i < $values.length; i++)
          {
              timeseries(id(this), $timeseries)
              .append (
                new Date($timeStamps[i]), 
                $values[i], 
                $tag);
          }",

      Values =
      {
          { "timeseries", "HeartRates" },
          { "timeStamps", timeStamps},
          { "values", values },
          { "tag", "watches/fitbit" }
      }
  }, null));

session.SaveChanges();

• In this sample, we remove a range of 50 time series entries from a document.

// Delete time-series entries
session.Advanced.Defer(new PatchCommandData("users/1-A", null,
  new PatchRequest
  {
      Script = @"timeseries(this, $timeseries)
               .delete(
                  $from, 
                  $to
                );",
      Values =
      {
          { "timeseries", "HeartRates" },
          { "from", baseline.AddSeconds(0) },
          { "to", baseline.AddSeconds(49) }
      }
  }, null));

session.SaveChanges();