Benjamin Ducke wrote: > Next, I put some attribute handling code back in bit by bit to see when > the trouble would start again. It did not take long. Basically, managing > SQL strings with db_init_string and db_set_string works fine, but as > soon as the attribute database is queried (using db_open_select_cursor), > the lockups come back in full number! > > SUMMARY > > * The problem does not originate in a specific DB driver (such as > DBF.EXE), but is buried deep in the basic functions if the GRASS DBMI lib. > > * The basic Vect_read_line and Vect_cat_get functions work fine on Win32 > by themselves. Trouble starts when there is interaction with DBMI calls. > > * The function db_open_select_cursor is at least one of the possible > culprits, but chances are that more functions are involved. In any case, > lockups occur more frequently when calls to Vect_read_line are done > often, suggesting that there is some unwholesome interaction or > competition for resources between Vect and DBMI libs. > > * For some reason, this problem does not show up in Linux. > There is strong evidence that it is a system resource allocation problem > (mem, file handlers???), because lockups occur less frequently on > systems with more available RAM. The problem exists on both Windows 2000 > and Windows XP systems (Vista untested). > > > > For today, I am giving up. > At least now it seems to become clearer where to look for the culprit. > If any of you have any bright ideas, I'd be grateful to hear about them.
My first guesses would be: 1. The "#ifdef __MINGW32__" portion of lib/db/dbmi_client/start.c 2. The Windows port of the RPC/XDR library. If the behaviour is non-deterministic (i.e. you don't get exactly the same behaviour from consecutive runs), I would suspect that it's timing related. Checking that incomplete read/write operations are correctly handled might be a good place to start. -- Glynn Clements <[EMAIL PROTECTED]> _______________________________________________ grass-dev mailing list [email protected] http://grass.itc.it/mailman/listinfo/grass-dev
