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| author | Vicențiu Ciorbaru <vicentiu@mariadb.org> | 2017-06-18 19:48:57 +0300 |
|---|---|---|
| committer | Vicențiu Ciorbaru <vicentiu@mariadb.org> | 2017-06-28 15:23:36 +0300 |
| commit | 90038693903044bbbf7946ac128c3757ad33d7ba (patch) | |
| tree | f3596c10eae1ed4d48ba5e4e6324ec5c63923aba /sql | |
| parent | b3171607e3e3024ea493c785831a7421a36fa7fe (diff) | |
| download | mariadb-git-90038693903044bbbf7946ac128c3757ad33d7ba.tar.gz | |
Simplify IO_CACHE by removing current_pos and end_pos as self-references
These self references were previously used to avoid having to check the
IO_CACHE's type. However, a benchmark shows that on x86 5930k stock,
the type comparison is marginally faster than the double pointer dereference.
For 40 billion my_b_tell calls, the difference is .1 seconds in favor of performing the
type check. (Basically there is no measurable difference)
To prevent bugs from copying the structure using the equals(=) operator,
and having to do the bookkeeping manually, remove these "convenience"
variables.
Diffstat (limited to 'sql')
| -rw-r--r-- | sql/filesort.cc | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/sql/filesort.cc b/sql/filesort.cc index 83c8442937e..2388dd759b5 100644 --- a/sql/filesort.cc +++ b/sql/filesort.cc @@ -1483,8 +1483,6 @@ int merge_many_buff(Sort_param *param, uchar *sort_buffer, if (flush_io_cache(to_file)) break; /* purecov: inspected */ temp=from_file; from_file=to_file; to_file=temp; - setup_io_cache(from_file); - setup_io_cache(to_file); *maxbuffer= (uint) (lastbuff-buffpek)-1; } cleanup: @@ -1492,7 +1490,6 @@ cleanup: if (to_file == t_file) { *t_file=t_file2; // Copy result file - setup_io_cache(t_file); } DBUG_RETURN(*maxbuffer >= MERGEBUFF2); /* Return 1 if interrupted */ |