基于PostgreSQL的流式计算数据库PipelineDB--一些重要的功能

PipelineDB一些重要功能，这里接列一下：

SQL的一些高级应用：

基于PostgreSQL的流式计算数据库PipelineDB

--Output Streams 基于汇总的前后比较

CREATE CONTINUOUS VIEW v_sum AS SELECT sum(x) FROM stream;

CREATE CONTINUOUS VIEW v_deltas AS SELECT abs((new).sum - (old).sum) AS delta

  FROM output_of('v_sum')

  WHERE abs((new).sum - (old).sum) > 10;

  --windows 范围

CREATE CONTINUOUS VIEW v_ttl WITH (ttl = '1 month', ttl_column = 'minute') AS

  SELECT minute(arrival_timestamp), COUNT(*) FROM some_stream GROUP BY minute;

--stream dispatch

CREATE CONTINUOUS TRANSFORM t AS

  SELECT x::int, y::int FROM stream WHERE mod(x, 2) = 0

  THEN EXECUTE PROCEDURE pipeline_stream_insert('even_stream');

数据字典/和执行统计查询

执行情况

pipeline_version ( )

pipeline_views ( )

pipeline_transforms ( )

统计数据

pipeline_query_stats

pipeline_stream_stats

备份/回复

具体见http://docs.pipelinedb.com/backups.html

pipeline-dump > backup.sql

pipeline -f backup.sql

Python连接

Python连接pipelinedb需要安装psycopg2,还是执行SQL语句，具体见http://docs.pipelinedb.com/clients.html

 import psycopg2

conn = psycopg2.connect('dbname=test user=user host=localhost port=5432')

pipeline = conn.cursor()

for x in range(10):

    rows.append({'x': x})



pipeline.executemany('INSERT INTO stream (x) VALUES (%(x)s)', rows)

 PS.

今天把剩下的版本<一切皆有价>看完了，信仰的价格这章很有意思，联想到前几天看的<量子物理史话>最后也变成的一个哲学问题

Matrix是无处不在的，也许这就是现实啊^-^