jgeek

db.createUser(
  {
    user: "da",
    pwd: "da@dp",
    roles: [ { role: "root", db: "admin" } ]
  }
)

jgeek

shards and reps
text field : ignore above
set 'doc_values'/'norms'/'index' for false to save disk if not necessary
set 'doc_values' to false: if sorting, scrpting and aggregation are not needed
setting norms to false: if relevance scoring is not needed
setting index to false: if do not need to filtering on values. still can be use for aggregation (time series) 
set dynamic_mapping to strict
dont always map strings to text and keyword
disable corecion
integer is enough than long and float often cover our need instead of double

jgeek

If you have two days to learn the very basics of modelling, Domain-Driven Design, CQRS and Event Sourcing, here's what you should do:

In the evenings read the [Domain-Driven Design Quickly Minibook]{http://www.infoq.com/minibooks/domain-driven-design-quickly}. During the day watch following great videos (in this order):

1. Eric Evans' [What I've learned about DDD since the book]{http://www.infoq.com/presentations/ddd-eric-evans}
2. Eric Evans' [Strategic Design - Responsibility Traps]{http://www.infoq.com/presentations/design-strategic-eric-evans}
3. Udi Dahan's [Avoid a Failed SOA: Business & Autonomous Components to the Rescue]{http://www.infoq.com/presentations/SOA-Business-Autonomous-Components}
4. Udi Dahan's [Command-Query Responsibility Segregation]{http://www.infoq.com/presentations/Command-Query-Responsibility-Segregation}
5. Greg Young's [Unshackle Your Domain]{http://www.infoq.com/presentations/greg-young-unshackle-qcon08}
6. Eric Evans' [Acknowledging CAP at the Root -- in the Domain Model]{ht

jgeek

The CLI have many options, but here are the other that are most commonly used:

Producer with keys

kafka-console-producer --broker-list 127.0.0.1:9092 --topic first_topic --property parse.key=true --property key.separator=,
> key,value
> another key,another value
Consumer with keys
--------

jgeek

Liskov Substitution Principle:
http://www.blackwasp.co.uk/squarerectangle.aspx

https://www.baeldung.com/solid-principles

jgeek

Cassandra uses a special type of primary key called a composite key (or compound
key) to represent groups of related rows, also called partitions. The composite key
consists of a partition key, plus an optional set of clustering columns. The partition key
is used to determine the nodes on which rows are stored and can itself consist of mul‐
tiple columns. The clustering columns are used to control how data is sorted for stor‐
age within a partition. Cassandra also supports an additional construct called a static
column, which is for storing data that is not part of the primary key but is shared by
every row in a partition.

So the outermost structure in Cassandra is the cluster, sometimes called

jgeek

https://booksites.artima.com/programming_in_scala_4ed/examples/

loan pattern: open a resource,operate on it, and then close the resource.

function literals, and function values
    Scala supports first-class functions, which means you can express functions in 
    function literal syntax, i.e., (x: Int) => x + 1 ,
    and that functions can be represented by objects, which are called function values.
    function literals and
    values is that function literals exist in the source code, whereas function val-

jgeek

# foreground and verbous
$ solr start -f -p 81 -V

# create core
$ ./solr create -c hellosolr

# -m heap size
$ solr start -p 8983 -h localhost -m 4g

# create core from sample config

jgeek

activator -Dactivator.checkForUpdates=false -jvm-debug 9999

jgeek

http://startbootstrap.com/template-overviews/thumbnail-gallery/