default of max_stack_depth
in [PgSql]
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From: Tom Lane on 6 Aug 2010 10:53 Fujii Masao <masao.fujii(a)gmail.com> writes: > On Fri, Aug 6, 2010 at 11:02 PM, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: >> The initial value needs to be small until we have been able to probe >> rlimit and figure out what is safe. > Thanks! How about adding the comment about that as follows? I added this: /* * We use the hopefully-safely-small value of 100kB as the compiled-in * default for max_stack_depth. InitializeGUCOptions will increase it if * possible, depending on the actual platform-specific stack limit. */ although I don't entirely see the point. We are certainly not going to comment every variable whose compiled-in default gets changed by later processing. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Tom Lane on 6 Aug 2010 10:02 Fujii Masao <masao.fujii(a)gmail.com> writes: > The document says that the max_stack_depth is 2MB by default. > OTOH, in the source code, the variable max_stack_depth is > initialized with 100 (kB), and guc.c also uses 100 as the > default. Why? The initial value needs to be small until we have been able to probe rlimit and figure out what is safe. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Fujii Masao on 6 Aug 2010 10:22 On Fri, Aug 6, 2010 at 11:02 PM, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: > Fujii Masao <masao.fujii(a)gmail.com> writes: >> The document says that the max_stack_depth is 2MB by default. >> OTOH, in the source code, the variable max_stack_depth is >> initialized with 100 (kB), and guc.c also uses 100 as the >> default. Why? > > The initial value needs to be small until we have been able to probe > rlimit and figure out what is safe. Thanks! How about adding the comment about that as follows? *** a/src/backend/utils/misc/guc.c --- b/src/backend/utils/misc/guc.c *************** *** 1520,1525 **** static struct config_int ConfigureNamesInt[] = --- 1520,1531 ---- 16384, 1024, MAX_KILOBYTES, NULL, NULL }, + /* + * Note: the real default of max_stack_depth is calculated in + * InitializeGUCOptions(). We use 100 as the sufficiently small + * initial value until we have been able to probe rlimit and + * figure out what is safe. + */ { {"max_stack_depth", PGC_SUSET, RESOURCES_MEM, gettext_noop("Sets the maximum stack depth, in kilobytes."), Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
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