vicly

聚集索引 : clustered index

• 把这种正文内容本身就是一种按照一定规则排列的目录称为“聚集索引”。如：汉语字典本身按照a-z排序，认识拼音的字，可以直接翻到字典到特定区间查，所有读音类似的字都在一起，如 ”术“，”书“
• 每个table只能有一个聚集索引
• 最大好处就是能够根据查询要求，迅速缩小查询范围，避免全表扫描

非聚集索引 : nonclustered index

• 把这种目录纯粹是目录，正文纯粹是正文的排序方式称为“非聚集索引”。如：不认识的字，必须先按偏旁查找目录，然后再翻到指定页数；注意，偏旁一样的字分散在不同的地方，如 "认"，“读”

误区：

vicly

BindingProvider bindingProvider = (BindingProvider) port;
    bindingProvider.getRequestContext().put(
          BindingProvider.ENDPOINT_ADDRESS_PROPERTY,
          "https://blah/blah/blah");

vicly

The phenomena which are prohibited at various levels are:

dirty read

A transaction reads data written by a concurrent uncommitted transaction.

nonrepeatable read

A transaction re-reads data it has previously read and finds that data has been modified by another transaction (that committed since the initial read).

phantom read

vicly

IP

• 公网IP唯一
• 内网IP不唯一，如公司A有192.168.0.1，公司B也有192.168.0.1

NAT

Network Address Translation

本地IP转为公网IP，便于内网机器使用有限公网IP访问互联网

vicly

Key:

• Don't use PATCH OR use it the right way
• PATCH is not to replace POST or PUT
• PATCH applies a delta rather than replacing the entire resource
• PATCH is of a different content-type
• PUT's payload is considered to be a modified version of the resource stored on the origin server, so the client is to replace it
• PATCH's payload contains a set of instructions about how to modify the resource on the origin server, so to produce a new version
• You can use whatever format you want as “description of changes”

vicly

Use Mockito V2, V1 does not support mocking final/static.

<dependency>
  <groupId>org.mockito</groupId>
  <artifactId>mockito-core</artifactId>
  <version>2.25.1</version>
</dependency>

vicly

DB Client 1

-- row 2 is locked
SELECT * FROM t_demo WHERE id=2 FOR UPDATE;

DB Client 2: BAD performace

vicly

https://kubernetes.io/docs/tutorials

K8S master node(single in the cluster) has three processes kube-apiserver, kube-controller-manager and kube-scheduler.

K8S non-master nodes have two processes kubelet(talks to master), kube-proxy(access cluster)

Basic Objects

vicly

CREATE TABLE product (
  id                 UUID		     PRIMARY KEY,
  name               VARCHAR(64)     NOT NULL,
  -- max 999999.9999
  price_amount       NUMERIC(10, 4)  NOT NULL CHECK (price_amount >= 0),
  price_currency     VARCHAR(10)     NOT NULL,
  created_at         TIMESTAMP WITH TIME ZONE NOT NULL,
  updated_at         TIMESTAMP WITH TIME ZONE NULL
);

vicly

AWS CloudWatch

https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_architecture.html

What's it

####How Cloud Watch Works