diff options
| author | Tom Lane | 2022-08-17 15:12:35 +0000 |
|---|---|---|
| committer | Tom Lane | 2022-08-17 15:12:35 +0000 |
| commit | efd0c16becbf45e3b0215e124fde75fee8fcbce4 (patch) | |
| tree | 4583c8e845ce18ae4a6c6b4c008a4989c514b3cb /src/backend/partitioning | |
| parent | 4a319fce7671ffbe2a730f79529b7a2ef3794d41 (diff) | |
Avoid using list_length() to test for empty list.
The standard way to check for list emptiness is to compare the
List pointer to NIL; our list code goes out of its way to ensure
that that is the only representation of an empty list. (An
acceptable alternative is a plain boolean test for non-null
pointer, but explicit mention of NIL is usually preferable.)
Various places didn't get that memo and expressed the condition
with list_length(), which might not be so bad except that there
were such a variety of ways to check it exactly: equal to zero,
less than or equal to zero, less than one, yadda yadda. In the
name of code readability, let's standardize all those spellings
as "list == NIL" or "list != NIL". (There's probably some
microscopic efficiency gain too, though few of these look to be
at all performance-critical.)
A very small number of cases were left as-is because they seemed
more consistent with other adjacent list_length tests that way.
Peter Smith, with bikeshedding from a number of us
Discussion: https://postgr.es/m/CAHut+PtQYe+ENX5KrONMfugf0q6NHg4hR5dAhqEXEc2eefFeig@mail.gmail.com
Diffstat (limited to 'src/backend/partitioning')
| -rw-r--r-- | src/backend/partitioning/partprune.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c index 9d3c05aed3b..fc19232c7b9 100644 --- a/src/backend/partitioning/partprune.c +++ b/src/backend/partitioning/partprune.c @@ -2383,7 +2383,7 @@ get_steps_using_prefix(GeneratePruningStepsContext *context, context->rel->part_scheme->strategy == PARTITION_STRATEGY_HASH); /* Quick exit if there are no values to prefix with. */ - if (list_length(prefix) == 0) + if (prefix == NIL) { PartitionPruneStep *step; |