R devel - Dec 2023 - Partial matching performance in data frame rownames using [

? Mon, 11 Dec 2023 21:11:48 +0100
Hilmar Berger via R-devel <r-devel at r-project.org> ?????:
> What was unexpected is that in this case was that [.data.frame was
> hanging for a long time (I waited about 10 minutes and then restarted
> R). Also, this cannot be interrupted in interactive mode.
That's unfortunate. If an operation takes a long time, it ought to be
interruptible. Here's a patch that passes make check-devel:

--- src/main/unique.c	(revision 85667)
+++ src/main/unique.c	(working copy)
@@ -1631,6 +1631,7 @@
 	}
     }
 
+    unsigned int ic = 9999;
     if(nexact < n_input) {
 	/* Second pass, partial matching */
 	for (R_xlen_t i = 0; i < n_input; i++) {
@@ -1642,6 +1643,10 @@
 	    mtch = 0;
 	    mtch_count = 0;
 	    for (int j = 0; j < n_target; j++) {
+		if (!--ic) {
+		    R_CheckUserInterrupt();
+		    ic = 9999;
+		}
 		if (no_dups && used[j]) continue;
 		if (strncmp(ss, tar[j], temp) == 0) {
 		    mtch = j + 1;

-- 
Best regards,
Ivan

Dear Ivan,

thanks a lot, that is helpful.

Still, I feel that default partial matching cripples the functionality
of data.frame for larger tables.

Thanks again and best regards

Hilmar

On 12.12.23 13:55, Ivan Krylov wrote:
> ? Mon, 11 Dec 2023 21:11:48 +0100
> Hilmar Berger via R-devel <r-devel at r-project.org> ?????:
>
>> What was unexpected is that in this case was that [.data.frame was
>> hanging for a long time (I waited about 10 minutes and then restarted
>> R). Also, this cannot be interrupted in interactive mode.
> That's unfortunate. If an operation takes a long time, it ought to be
> interruptible. Here's a patch that passes make check-devel:
>
> --- src/main/unique.c	(revision 85667)
> +++ src/main/unique.c	(working copy)
> @@ -1631,6 +1631,7 @@
>   	}
>       }
>
> +    unsigned int ic = 9999;
>       if(nexact < n_input) {
>   	/* Second pass, partial matching */
>   	for (R_xlen_t i = 0; i < n_input; i++) {
> @@ -1642,6 +1643,10 @@
>   	    mtch = 0;
>   	    mtch_count = 0;
>   	    for (int j = 0; j < n_target; j++) {
> +		if (!--ic) {
> +		    R_CheckUserInterrupt();
> +		    ic = 9999;
> +		}
>   		if (no_dups && used[j]) continue;
>   		if (strncmp(ss, tar[j], temp) == 0) {
>   		    mtch = j + 1;
>