diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/utils/misc/guc.c | 52 |
1 files changed, 31 insertions, 21 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 3c695c16153..da74f00ab24 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -8903,7 +8903,9 @@ can_skip_gucvar(struct config_generic * gconf) /* * estimate_variable_size: - * Estimate max size for dumping the given GUC variable. + * Compute space needed for dumping the given GUC variable. + * + * It's OK to overestimate, but not to underestimate. */ static Size estimate_variable_size(struct config_generic * gconf) @@ -8914,9 +8916,8 @@ estimate_variable_size(struct config_generic * gconf) if (can_skip_gucvar(gconf)) return 0; - size = 0; - - size = add_size(size, strlen(gconf->name) + 1); + /* Name, plus trailing zero byte. */ + size = strlen(gconf->name) + 1; /* Get the maximum display length of the GUC value. */ switch (gconf->vartype) @@ -8937,7 +8938,7 @@ estimate_variable_size(struct config_generic * gconf) * small values. Maximum value is 2147483647, i.e. 10 chars. * Include one byte for sign. */ - if (abs(*conf->variable) < 1000) + if (Abs(*conf->variable) < 1000) valsize = 3 + 1; else valsize = 10 + 1; @@ -8947,11 +8948,12 @@ estimate_variable_size(struct config_generic * gconf) case PGC_REAL: { /* - * We are going to print it with %.17g. Account for sign, - * decimal point, and e+nnn notation. E.g. - * -3.9932904234000002e+110 + * We are going to print it with %e with REALTYPE_PRECISION + * fractional digits. Account for sign, leading digit, + * decimal point, and exponent with up to 3 digits. E.g. + * -3.99329042340000021e+110 */ - valsize = REALTYPE_PRECISION + 1 + 1 + 5; + valsize = 1 + 1 + 1 + REALTYPE_PRECISION + 5; } break; @@ -8959,7 +8961,15 @@ estimate_variable_size(struct config_generic * gconf) { struct config_string *conf = (struct config_string *) gconf; - valsize = strlen(*conf->variable); + /* + * If the value is NULL, we transmit it as an empty string. + * Although this is not physically the same value, GUC + * generally treats a NULL the same as empty string. + */ + if (*conf->variable) + valsize = strlen(*conf->variable); + else + valsize = 0; } break; @@ -8972,17 +8982,17 @@ estimate_variable_size(struct config_generic * gconf) break; } - /* Allow space for terminating zero-byte */ + /* Allow space for terminating zero-byte for value */ size = add_size(size, valsize + 1); if (gconf->sourcefile) size = add_size(size, strlen(gconf->sourcefile)); - /* Allow space for terminating zero-byte */ + /* Allow space for terminating zero-byte for sourcefile */ size = add_size(size, 1); - /* Include line whenever we include file. */ - if (gconf->sourcefile) + /* Include line whenever file is nonempty. */ + if (gconf->sourcefile && gconf->sourcefile[0]) size = add_size(size, sizeof(gconf->sourceline)); size = add_size(size, sizeof(gconf->source)); @@ -9100,7 +9110,7 @@ serialize_variable(char **destptr, Size *maxbytes, { struct config_real *conf = (struct config_real *) gconf; - do_serialize(destptr, maxbytes, "%.*g", + do_serialize(destptr, maxbytes, "%.*e", REALTYPE_PRECISION, *conf->variable); } break; @@ -9109,7 +9119,9 @@ serialize_variable(char **destptr, Size *maxbytes, { struct config_string *conf = (struct config_string *) gconf; - do_serialize(destptr, maxbytes, "%s", *conf->variable); + /* NULL becomes empty string, see estimate_variable_size() */ + do_serialize(destptr, maxbytes, "%s", + *conf->variable ? *conf->variable : ""); } break; @@ -9126,7 +9138,7 @@ serialize_variable(char **destptr, Size *maxbytes, do_serialize(destptr, maxbytes, "%s", (gconf->sourcefile ? gconf->sourcefile : "")); - if (gconf->sourcefile) + if (gconf->sourcefile && gconf->sourcefile[0]) do_serialize_binary(destptr, maxbytes, &gconf->sourceline, sizeof(gconf->sourceline)); @@ -9193,7 +9205,7 @@ read_gucstate(char **srcptr, char *srcend) for (ptr = *srcptr; ptr < srcend && *ptr != '\0'; ptr++) ; - if (ptr > srcend) + if (ptr >= srcend) elog(ERROR, "could not find null terminator in GUC state"); /* Set the new position to the byte following the terminating NUL */ @@ -9247,9 +9259,7 @@ RestoreGUCState(void *gucstate) { int result; - if ((varname = read_gucstate(&srcptr, srcend)) == NULL) - break; - + varname = read_gucstate(&srcptr, srcend); varvalue = read_gucstate(&srcptr, srcend); varsourcefile = read_gucstate(&srcptr, srcend); if (varsourcefile[0]) |