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
Latency Comparison Numbers (~2012) | |
---------------------------------- | |
L1 cache reference 0.5 ns | |
Branch mispredict 5 ns | |
L2 cache reference 7 ns 14x L1 cache | |
Mutex lock/unlock 25 ns | |
Main memory reference 100 ns 20x L2 cache, 200x L1 cache | |
Compress 1K bytes with Zippy 3,000 ns 3 us | |
Send 1K bytes over 1 Gbps network 10,000 ns 10 us | |
Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD |
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 python2 | |
import SimpleHTTPServer | |
import SocketServer | |
import logging | |
PORT = 8000 | |
class GetHandler(SimpleHTTPServer.SimpleHTTPRequestHandler): |
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
# This is just a cheat sheet: | |
# On production | |
sudo -u postgres pg_dump database | gzip -9 > database.sql.gz | |
# On local | |
scp -C production:~/database.sql.gz | |
dropdb database && createdb database | |
gunzip < database.sql.gz | psql database |
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
Backup: | |
docker exec -t -u postgres your-db-container pg_dumpall -c > dump_`date +%d-%m-%Y"_"%H_%M_%S`.sql | |
Restore: | |
cat your_dump.sql | docker exec -i your-db-container psql -Upostgres |
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
--- PSQL queries which also duplicated from https://github.com/anvk/AwesomePSQLList/blob/master/README.md | |
--- some of them taken from https://www.slideshare.net/alexeylesovsky/deep-dive-into-postgresql-statistics-54594192 | |
-- I'm not an expert in PSQL. Just a developer who is trying to accumulate useful stat queries which could potentially explain problems in your Postgres DB. | |
------------ | |
-- Basics -- | |
------------ | |
-- Get indexes of tables |