
Improve your Odoo PostgreSQL performance
You probably have noticed already that Odoo and PostgreSQL are installed in separate packages. That should give you the following clue:
The standard PostgreSQL installation is neither optimized for your hardware not for your Odoo
Before you move into running PostgreSQL with your Odoo and through Python-driven requests, here is a list of the things you should do to give your system a real chance to run decently:
PostgreSQL logging
- Be generous with logging; it’s very low-impact on the system
- Locations for logs are better managed by syslog.
- Just use:
log_destination = ‘csvlog’
log_directory = ‘pg_log’
Shared_buffers
work_mem
- Start low: 32-64MB
- Look for ‘temporary file’ lines in logs
- set to 2-3x the largest temp file you see
- Can cause a huge speed-up if set properly
- Be careful: it can use that amount of memory per query
maintenance_work_mem
- Set to 10% of system memory, up to 1GB
effective_cache_size
- Set to the amount of file system cache available
- If you don’t know it, set it to 50% of the available memory
Checkpointing
- A complete fish of dirty buffers to disk
- Potentially a lot of I/O
Easy performance boosts
- Don’t run anything else on your PostgreSQL server
- If PostgreSQL is in a VM, remember all of the other VMs on the same host
- Disable the Linux OOM killer
Stupid Database Tricks
- Don’t put your sessions in the database
- Avoid aonstantly-updated accumulator records.
- Don’t put the task queues in the database
- Don’t use the database as a filesystem
- Don’t use frequently-locked singleton records
- Don’t use very long-running transactions
- Mixing transactional and data warehouse queries on the same database
One schema trick
- If one model ha sa constantly-updated section and a rarely-updated section
- last-seen on site field
- cut out that field into a new model
SQL Pathologies
- Gigantic IN clauses (a typical Django anti-pattern) are problematic
- Unanchored text queries like ‘%this%’ run slow
Indexing
- A good index has high selectivity on commonly-used data and will return a small number of records
- A good infex is determined by analysis, not guessing
- Use pg_stat_user_tables – shows sequential scans
- Use pg_stat_index_blah
Vacuuming
- autovacuum slowing the system down? Increase autovacuum_vacuum_cost_limit in small increments
- If the load is periodic, do manual VACUUMing instead at low-low times
- You must VACUUM on a regular basis
- Analyze your vacuum
- Collect statistics on the data to help the planner choose a good plan
On-going maintenance and monitoring
- Keep track of disk space and system load
- memory and I/O utilization is very handy
- 1 minute bnts
- check_posgres.pl at bucardo.org
2 different orientation for Backups
pg_dump
- Easiest backup tool for PostgreSQL
- Low impact on a running database
- Makes a copy of the database
- becomes impractical for large databases
Streaming replication
- Best solution for large databases
- Easy to set up
- Maintains an exact logical copy of the database on a different host
- Does not guard against application-level failures, however
- Can be used for read-only queries
- if you are getting query cancellations then bump up a config
- Is all-or-nothing
- If you need partial replication, you need to use Slony or Bucardo
- ..warning:: partial replication is a full-time effort
WAL Archiving
- Maintains a set of base backups and WAL segments on a remote server
- Can be used for point-in-time recovery in case of an application (or DBA) failure
- Slightly more complex to set up
Encodings
- Character encoding is fixed in a database when created
- The defaults are not what you want
- Use UTF-8 encoding
Migrations
- All modifications to a table take an exclusive lock on that table while the modification is being done.
- If you add a column with a default value, the table will be rewritten
- Migrating a big table
- Create the column as NOT NULL
- Add constraint later once field is populated
- Note
Vacuum FREEZE
- Once in a while PostgreSQL needs to scan every table
- THis can be a very big surprise
- Run VACUUM manually periodically
Hardware
- Get lots of ECC RAM
- CPU is not as vital as RAM
- Use a RAID
Big data / Data growth