Blog

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

After you run this, you may want to adjust the aggressiveness of your autovacuum settings to avoid accumulating more bloat in the future. The following settings should be considered:

  • autovacuum_max_workers  = 5 - This is is the recommended setting recommended setting for a 16-core machine. If you have, for example, a 4-core, a setting of 2 would be the best available option.
  • autovacuum_vacuum_scale_factor = 0.02 - This setting indicates the threshold which determines when autovacuum needs to run per table. It refers to the fraction of the table size. So if the percentage of dead tuples (the pfrag column in the SQL query above) is greater than 2%, this spawns an autovacuum process. The default value for this setting is 20%, which will create massive bloat in your database before the autovacuum process even starts.
  • autovacuum_analyze_scale_factor = 0.01 - Although not specific to table size and vacuum cleanup, this setting, which is also a percentage of fragmentation of the table, tells the autovacuum process to analyze the table (i.e., update query planner statistics) when the fragmentation percentage reaches 1% (the default is 10%).

...