diff --git a/funcs/func_odbc.c b/funcs/func_odbc.c
index d1ca07d..988bc58 100644
--- a/funcs/func_odbc.c
+++ b/funcs/func_odbc.c
@@ -109,9 +109,11 @@ struct acf_odbc_query {
 	AST_RWLIST_ENTRY(acf_odbc_query) list;
 	char readhandle[5][30];
 	char writehandle[5][30];
-	char sql_read[2048];
-	char sql_write[2048];
-	char sql_insert[2048];
+	/* Using AST_REALTIME_DATA_MINLEN because these values can be read from
+	 * from the static realtime var_val column. */
+	char sql_read[AST_REALTIME_DATA_MINLEN];
+	char sql_write[AST_REALTIME_DATA_MINLEN];
+	char sql_insert[AST_REALTIME_DATA_MINLEN];
 	unsigned int flags;
 	int rowlimit;
 	struct ast_custom_function *acf;
diff --git a/include/asterisk/config.h b/include/asterisk/config.h
index 86c2bb5..33fb256 100644
--- a/include/asterisk/config.h
+++ b/include/asterisk/config.h
@@ -30,6 +30,22 @@ extern "C" {
 #include "asterisk/utils.h"
 #include "asterisk/inline_api.h"
 
+/*! When using realtime database features, you can safely assume that your
+ * column data can be up to this many bytes in length (minus the trailing
+ * NUL) unless specified otherwise.
+ *
+ * Of course you are free to make your column smaller if you don't have any
+ * large data. If you make your column larger, Asterisk won't guarantee that
+ * the data won't be truncated.
+ *
+ * For example:
+ * - the static realtime var_val column, which can the value part of any
+ *   configuration file;
+ * - the dynamic realtime sippeer setvar column, which is otherwise of
+ *   unspecified length.
+ */
+#define AST_REALTIME_DATA_MINLEN 2048
+
 struct ast_config;
 
 struct ast_category;
diff --git a/res/res_config_odbc.c b/res/res_config_odbc.c
index ef0d735..bd17f53 100644
--- a/res/res_config_odbc.c
+++ b/res/res_config_odbc.c
@@ -153,7 +153,7 @@ static struct ast_variable *realtime_odbc(const char *database, const char *tabl
 	SQLHSTMT stmt;
 	char sql[1024];
 	char coltitle[256];
-	char rowdata[2048];
+	char rowdata[AST_REALTIME_DATA_MINLEN];
 	char *op;
 	const char *newparam;
 	char *stringp;
@@ -320,7 +320,7 @@ static struct ast_config *realtime_multi_odbc(const char *database, const char *
 	SQLHSTMT stmt;
 	char sql[1024];
 	char coltitle[256];
-	char rowdata[2048];
+	char rowdata[AST_REALTIME_DATA_MINLEN];
 	const char *initfield;
 	char *op;
 	const char *newparam;
@@ -879,7 +879,7 @@ struct config_odbc_obj {
 	unsigned long cat_metric;
 	char category[128];
 	char var_name[128];
-	char var_val[1024]; /* changed from 128 to 1024 via bug 8251 */
+	char var_val[AST_REALTIME_DATA_MINLEN];
 	SQLLEN err;
 };
 
@@ -927,12 +927,10 @@ static struct ast_config *config_odbc(const char *database, const char *table, c
 	SQLSMALLINT rowcount = 0;
 	SQLHSTMT stmt;
 	char last[128] = "";
-	struct config_odbc_obj q;
+	struct config_odbc_obj q = { 0 };
 	struct ast_flags loader_flags = { 0 };
 	struct ast_flags connected_flag = { RES_ODBC_CONNECTED };
 
-	memset(&q, 0, sizeof(q));
-
 	if (!file || !strcmp (file, "res_config_odbc.conf"))
 		return NULL;		/* cant configure myself with myself ! */