The OpenLogic Technical Support Team fields lots of questions on PostgreSQL and over 500 other open source packages. They’ve distilled decades of experience and hundreds of PostgreSQL support issues down to the most common questions.
| General Questions | |
|---|---|
| Is it possible to completely disable the operational behavior of bgwriter_all_percent? | To disable bgwriter_all_percent and/or bgwriter_max_pages completely, set both maxpages values and/or both percent values to zero in postgresql.conf, the configuration file. |
| Is there any way to prevent lazy_truncate_heap() from executing? | The best solution for this known issue is to update to the 8.x branch. |
| Can VACUUM execution occur at a time when SELECTS will not occur? | Beginning with version 8, PostgreSQL has been enhanced to prevent VACUUM from blocking SELECTS. We strongly recommend updating to version 8 or higher as it includes many new options for tuning VACUUM. |
| How do I disable bgwriter_all_percent and enable only bg_writer_max_pages, or enable only bgwriter_all_percent? | To quit the behavior (operation) of bgwriter_all_percent completely, use any one of the following sets of settings:
--------------------------------------------------------- bgwriter_all_percent = 0 bgwriter_all_maxpages = 0 --------------------------------------------------------- bgwriter_all_percent = .333 bgwriter_all_maxpages = 0 --------------------------------------------------------- bgwriter_all_percent = 0 bgwriter_all_maxpages = 5 --------------------------------------------------------- In the case of bgwriter_lru, use any one of the same combinations, as indicated below. --------------------------------------------------------- bgwriter_lru_percent = 0 bgwriter_lru_maxpages = 0 --------------------------------------------------------- bgwriter_lru_percent = .333 bgwriter_lru_maxpages = 0 --------------------------------------------------------- bgwriter_lru_percent = 0 bgwriter_lru_maxpages = 5 --------------------------------------------------------- For additional information, please reference the PostgreSQL documentation on this issue at http://www.postgresql.org/docs/current/static/runtime-config-resource.html, or contact OpenLogic customer support. |
