On Tue, Feb 7, 2017 at 3:01 PM, Mithun Cy <mithun...@enterprisedb.com> wrote:
> On Tue, Feb 7, 2017 at 11:53 AM, Beena Emerson <memissemer...@gmail.com> > wrote: > > launched by other applications. Also with max_worker_processes = 2 and > > restart, the system crashes when the 2nd worker is not launched: > > 2017-02-07 11:36:39.132 IST [20573] LOG: auto pg_prewarm load : number > of > > buffers actually tried to load 64 > > 2017-02-07 11:36:39.143 IST [18014] LOG: worker process: auto pg_prewarm > > load (PID 20573) was terminated by signal 11: Segmentation fault > > SEGFAULT was the coding mistake I have called the C-language function > directly without initializing the functioncallinfo. Thanks for > raising. Below patch fixes same. > > -- > Thanks and Regards > Mithun C Y > EnterpriseDB: http://www.enterprisedb.com > Few more comments: = Background worker messages: - Workers when launched, show messages like: "logical replication launcher started”, "autovacuum launcher started”. We should probably have a similar message to show that the pg_prewarm load and dump bgworker has started. - "auto pg_prewarm load: number of buffers to load x”, other messages show space before and after “:”, we should keep it consistent through out. = Action of -1. I thought we decided that interval value of -1 would mean that the auto prewarm worker will not be run at all. With current code, -1 is explained to mean it will not dump. I noticed that reloading with new option as -1 stops both the workers but restarting loads the data and then quits. Why does it allow loading with -1? Please explain this better in the documents. = launch_pg_prewarm_dump() With dump_interval=-1, Though function returns a pid, this worker is not running in the 04 patch. 03 version it was launching. Dumping is not done now. =# SELECT launch_pg_prewarm_dump(); launch_pg_prewarm_dump ------------------------ 53552 (1 row) $ ps -ef | grep 53552 b_emers+ 53555 4391 0 16:21 pts/1 00:00:00 grep --color=auto 53552 = Function names - load_now could be better named as load_file, load_dumpfile or similar. - dump_now -> dump_buffer or better? = Corrupt file if the dump file is corrupted, the system crashes and the prewarm bgworkers are not restarted. This needs to be handled better. WARNING: terminating connection because of crash of another server process 2017-02-07 16:36:58.680 IST [54252] DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory = Documentation I feel the documentation needs to be improved greatly. - The first para in pg_prewarm should mention the autoload feature too. - The new section should be named “The pg_prewarm autoload” or something better. "auto pg_prewarm bgworker” does not seem appropriate. The configuration parameter should also be listed out clearly like in auth-delay page. The new function launch_pg_prewarm_dump() should be listed under Functions. -- Thank you, Beena Emerson Have a Great Day!
