EshaMaharishi

#!/usr/bin/env python3
"""Plot safetyMonitored* call durations from viam-server log."""

import re
import sys
import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import numpy as np

EshaMaharishi

#!/usr/bin/env python3
"""Plot per-step MoveThroughJointPositions call durations.

Usage: python3 plot_step_times.py [step_times.csv] [output.png]
"""
import csv
import sys

import matplotlib
matplotlib.use("Agg")

EshaMaharishi

package main

import (
	"context"
	"crypto/tls"
	"flag"
	"fmt"
	"os"
	"time"

EshaMaharishi

diff --git a/robot/session_web.go b/robot/session_web.go
index 8d6a3f919..ea0ef4f90 100644
--- a/robot/session_web.go
+++ b/robot/session_web.go
@@ -2,8 +2,10 @@ package robot
 
 import (
 	"context"
+	"fmt"
 	"strings"

EshaMaharishi

diff --git a/robot/session_web.go b/robot/session_web.go
index 8d6a3f919..ea0ef4f90 100644
--- a/robot/session_web.go
+++ b/robot/session_web.go
@@ -2,8 +2,10 @@ package robot
 
 import (
 	"context"
+	"fmt"
 	"strings"

EshaMaharishi

diff --git a/etc/evergreen.yml b/etc/evergreen.yml
index ec8835979cc..aa83986c473 100644
--- a/etc/evergreen.yml
+++ b/etc/evergreen.yml
@@ -419,9 +419,10 @@ buildvariants:
   - name: .stitch
   - name: secondary_reads_passthrough_gen
   - name: server_discovery_and_monitoring_json_test_TG
-  - name: .serverless !.multiversion
-    distros:

EshaMaharishi

Script:

```
const st = new ShardingTest({shards: {rs0: {nodes: 2}}, config: 1, other: { mongosOptions: {verbose: 3}}});

for (let i = 0; i < 1000; i++) {
    st.s.getDB("test").foo.insert({_id: i});
}

let cursor = st.s.getDB("test").foo.find().readPref('secondary');

EshaMaharishi

Debugging MongoDB with gdb

gdb is a command line tool that you can use to examine the state of a (1) terminated or (2) running C or C++ process.

Background: Debugging a terminated process

A process can terminate (uncleanly) for a few reasons, such as triggering a segmentation fault, failing an invariant, or throwing an uncaught exception.

A binary can be compiled so that when a process terminates (uncleanly), the process produces a core dump, which is a file containing a "frozen" record of the state of all threads that existed in the process at the time it terminated.

EshaMaharishi

The Decorator Pattern

A Decoration is an object that is stored as part of another object, called the Decorable.

The lifetime of the Decoration is tied to the lifetime of the Decorable. This means the Decoration is constructed when the Decorable's constructor is called, and the Decoration is destructed when the Decorable's destructor is called.

Finally, the decoration can only be accessed through the decorable.

The Decorator pattern is an easy way to add parts to an existing object without changing the object.

EshaMaharishi

Sharding

This document provides MongoDB server engineers and community contributors with a "mental map" of sharding components and code.

A reader should have a basic understanding of sharding from a user's point of view.

Links to code reference the 3.4 release of MongoDB.

Links to online documentation reference the official MongoDB docs.