diff options
| -rw-r--r-- | src/backend/utils/misc/guc.c | 12 | ||||
| -rw-r--r-- | src/include/utils/guc_tables.h | 10 |
2 files changed, 20 insertions, 2 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index c410ba532d2..0b5b77b0003 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -9950,7 +9950,14 @@ get_explain_guc_options(int *num) { struct config_string *lconf = (struct config_string *) conf; - modified = (strcmp(lconf->boot_val, *(lconf->variable)) != 0); + if (lconf->boot_val == NULL && + *lconf->variable == NULL) + modified = false; + else if (lconf->boot_val == NULL || + *lconf->variable == NULL) + modified = true; + else + modified = (strcmp(lconf->boot_val, *(lconf->variable)) != 0); } break; @@ -10694,7 +10701,8 @@ write_one_nondefault_variable(FILE *fp, struct config_generic *gconf) { struct config_string *conf = (struct config_string *) gconf; - fprintf(fp, "%s", *conf->variable); + if (*conf->variable) + fprintf(fp, "%s", *conf->variable); } break; diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h index 067d82ada95..47e7819018e 100644 --- a/src/include/utils/guc_tables.h +++ b/src/include/utils/guc_tables.h @@ -227,6 +227,16 @@ struct config_real void *reset_extra; }; +/* + * A note about string GUCs: the boot_val is allowed to be NULL, which leads + * to the reset_val and the actual variable value (*variable) also being NULL. + * However, there is no way to set a NULL value subsequently using + * set_config_option or any other GUC API. Also, GUC APIs such as SHOW will + * display a NULL value as an empty string. Callers that choose to use a NULL + * boot_val should overwrite the setting later in startup, or else be careful + * that NULL doesn't have semantics that are visibly different from an empty + * string. + */ struct config_string { struct config_generic gen; |