kmatt

WITH upsert AS (
	UPDATE target 
	SET col1 = s.col1,
	    col2 = s.col2,
	    ...
	FROM source s
	WHERE s.key = target.key
	RETURNING s.*
)
INSERT INTO target ( ... )

kmatt

Types of index scans

Indexes

Sequential Scan:

• Read every row in the table
• No reading of index. Reading from indexes is also expensive.

kmatt

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BBEDIT/TEXTWRANGLER REGULAR EXPRESSION GUIDE                             MODIFIED 2014-01-13 : 00:12
————————————————————————————————————————————————————————————————————————————————————————————————————

NOTES: 

The PCRE engine (Perl Compatible Regular Expressions) is what BBEdit and TextWrangler use.

Items I'm unsure of are marked '# PCRE?'.  The list while fairly comprehensive is not complete.

kmatt

#Based on https://cwiki.apache.org/confluence/display/DRILL/Compiling+Drill+from+source

wget http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo

yum install apache-maven
ln -s /usr/share/apache-maven/bin/mvn /usr/bin/

yum install java-1.7.0-openjdk.x86_64
yum install java-1.7.0-openjdk-devel

kmatt

import urlparse
import argparse
import redis
import sys
from multiprocessing import Pool
import signal

def parse_redis_url(s):
    url = urlparse.urlparse(s)
    if not url.scheme:

kmatt

library(plyr)

find_zones <- function(x) {
  x.mean <- mean(x)
  x.sd <- sd(x)
  boundaries <- seq(-4, 4)
  # creates a set of zones for each point in x
  zones <- sapply(boundaries, function(i) {
    i * rep(x.sd, length(x))
  })

kmatt

WITH btree_index_atts AS (
    SELECT nspname, relname, reltuples, relpages, indrelid, relam,
        regexp_split_to_table(indkey::text, ' ')::smallint AS attnum,
        indexrelid as index_oid
    FROM pg_index
    JOIN pg_class ON pg_class.oid=pg_index.indexrelid
    JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace
    JOIN pg_am ON pg_class.relam = pg_am.oid
    WHERE pg_am.amname = 'btree'
    ),

kmatt

#!/usr/bin/env python
"""Export CSV from an RRD XML dump.

Usage: rrdxml.py file.xml rra

Where rra is the 0-based index for the RRA you want to dump.

"""
from csv import writer
from itertools import chain, izip

kmatt

If make fails with "failed to resolve INP_IPV4":

$ pwd
/usr/ports/databases/postgresql94-server

$ kldload dtraceall
$ echo"dtraceall_load=YES" >> /boot/loader.conf
$ make

kmatt

# 16GB RAM / 6 x 10K RPM HDDs striped / 4 CPU
# DWH / OLAP workloads - 128K blocksize providing better querytimes
# Using old benchw datasets to compare platforms (http://benchw.sourceforge.net/)

# Started with these at OS install defaults, subsequently adjusting between 2 - 8 GB
kern.ipc.shmmax=8576069632
kern.ipc.shmall=2093767
kern.ipc.semmap=256

NAME           PROPERTY              VALUE                  SOURCE