b4de30fb01a1168eadfcc65206714f1573eef8c9
max
  Tue Mar 10 06:31:07 2015 -0700
a mirror that has the failover connection (=hgdownload) enabled
currently just crashes in hgTables. Adding an additional check
to catch this condition and suppress printing the example values,
just like what we do for custom tracks.
refs #14945

diff --git src/hg/inc/jksql.h src/hg/inc/jksql.h
index f6632c2..1d5aa67 100644
--- src/hg/inc/jksql.h
+++ src/hg/inc/jksql.h
@@ -472,30 +472,34 @@
 
 char** sqlGetEnumDef(struct sqlConnection *conn, char* table, char* colName);
 /* Get the definitions of a enum column in a table, returning a
  * null-terminated array of enum values.  Free array when finished.  */
 
 struct slName *sqlRandomSample(char *db, char *table, char *field, int count);
 /* Get random sample from database. */
 
 struct slName *sqlRandomSampleConn(struct sqlConnection *conn, char *table,
 				   char *field, int count);
 /* Get random sample from conn. */
 
 struct slName *sqlRandomSampleWithSeed(char *db, char *table, char *field, int count, int seed);
 /* Get random sample from database specifiying rand number seed, or -1 for none */
 
+bool sqlCanCreateTemp(struct sqlConnection *conn);
+/* Return True if it looks like we can write into temp tables in the current database
+ * Can be used to check if sqlRandomSampleWithSeed-functions are safe to call.
+ * */
 
 struct sqlFieldInfo
 /* information about fields of a table; free with sqlFieldInfoFreeList */
 {
     struct sqlFieldInfo *next;
     char *field;          /* name of field */
     char *type;           /* type of field */
     boolean allowsNull;   /* can the field be NULL? */
     char *key;            /* key information */
     char *defaultVal;     /* default value */
     char *extra;          /* extra info */
 };
 
 struct sqlFieldInfo *sqlFieldInfoGet(struct sqlConnection *conn, char *table);
 /* get a list of objects describing the fields of a table */