- Read every row in the table
- No reading of index. Reading from indexes is also expensive.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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 ( ... ) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
———————————————————————————————————————————————————————————————————————————————————————————————————— | |
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. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#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 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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: |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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)) | |
}) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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' | |
), |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/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 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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 |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# 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 |
OlderNewer