On 12/20/2017 04:08 PM, mark wrote: > I have set shared_buffers is 1/4 of memory. > work_mem is 2% of memory. > max_connections is 50.
That means if you have all 50 connections active, they may easily consume 100% of memory, because 50 * 2 is 100. It's even easier if the connections are executing complex queries, because each query may use multiple work_mem buffers. So 2% seems a bit too high. > momery size is 16GB. > postgresql process used over 70% of memory and occuered OOM. So, did a single process use 70% of memory, or all postgres processes combined? If just a single process, it might be a poor plan choice (e.g. hash aggregate may easily cause that). If all processes combined, then perhaps it's due to work_mem being too high. > what should I do to deal with this problem? > Hard to say, until you provide enough information. regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
