diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-07-12 16:30:36 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-07-12 16:30:36 -0400 |
| commit | af72b0889441e5ece199f782511d84d72fa6b88c (patch) | |
| tree | c3a419f5a45ddd69ef4eb9efbabdd0f9fc59d859 /src/include | |
| parent | 5e7608e81ebb2a9e2a72ab771eba3c620c0b42a6 (diff) | |
Invent qsort_interruptible().
Justin Pryzby reported that some scenarios could cause gathering
of extended statistics to spend many seconds in an un-cancelable
qsort() operation. To fix, invent qsort_interruptible(), which is
just like qsort_arg() except that it will also do CHECK_FOR_INTERRUPTS
every so often. This bloats the backend by a couple of kB, which
seems like a good investment. (We considered just enabling
CHECK_FOR_INTERRUPTS in the existing qsort and qsort_arg functions,
but there are some callers for which that'd demonstrably be unsafe.
Opt-in seems like a better way.)
For now, just apply qsort_interruptible() in statistics collection.
There's probably more places where it could be useful, but we can
always change other call sites as we find problems.
Back-patch to v14. Before that we didn't have extended stats on
expressions, so that the problem was less severe. Also, this patch
depends on the sort_template infrastructure introduced in v14.
Tom Lane and Justin Pryzby
Discussion: https://postgr.es/m/20220509000108.GQ28830@telsasoft.com
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/port.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/include/port.h b/src/include/port.h index 82f63de3250..b405d0e7403 100644 --- a/src/include/port.h +++ b/src/include/port.h @@ -508,6 +508,9 @@ typedef int (*qsort_arg_comparator) (const void *a, const void *b, void *arg); extern void qsort_arg(void *base, size_t nel, size_t elsize, qsort_arg_comparator cmp, void *arg); +extern void qsort_interruptible(void *base, size_t nel, size_t elsize, + qsort_arg_comparator cmp, void *arg); + extern void *bsearch_arg(const void *key, const void *base, size_t nmemb, size_t size, int (*compar) (const void *, const void *, void *), |