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| author | Varun Gupta <varun.gupta@mariadb.com> | 2020-03-10 04:56:38 +0530 |
|---|---|---|
| committer | Varun Gupta <varun.gupta@mariadb.com> | 2020-03-10 15:09:17 +0530 |
| commit | b753ac066bc26acda9deb707a31c112f1bbf9ec2 (patch) | |
| tree | 6667ed652cf893a5c695b1ce6b621f54d5f0fdc9 /sql/uniques.cc | |
| parent | 561b5ce3647a63c343f70ce183e408423b3fa65c (diff) | |
| download | mariadb-git-b753ac066bc26acda9deb707a31c112f1bbf9ec2.tar.gz | |
MDEV-21580: Allow packed sort keys in sort buffer
This task deals with packing the sort key inside the sort buffer, which would
lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have sort keys of variable length
2) The format for sort keys inside the sort buffer would look like
|<sort_length><null_byte><key_part1><null_byte><key_part2>.......|
sort_length is the extra bytes that are required to store the variable
length of a sort key.
3) When packing of sort key is done we store the ORIGINAL VALUES inside
the sort buffer and not the STRXFRM form (mem-comparable sort keys).
4) Special comparison function packed_keys_comparison() is introduced
to compare 2 sort keys.
This patch also contains contributions from Sergei Petrunia.
Diffstat (limited to 'sql/uniques.cc')
| -rw-r--r-- | sql/uniques.cc | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/sql/uniques.cc b/sql/uniques.cc index 931aa868199..db9891158b0 100644 --- a/sql/uniques.cc +++ b/sql/uniques.cc @@ -531,7 +531,7 @@ static bool merge_walk(uchar *merge_buffer, size_t merge_buffer_size, top->set_buffer(merge_buffer + (top - begin) * piece_size, merge_buffer + (top - begin) * piece_size + piece_size); top->set_max_keys(max_key_count_per_piece); - bytes_read= read_to_buffer(file, top, &sort_param); + bytes_read= read_to_buffer(file, top, &sort_param, false); if (unlikely(bytes_read == (ulong) -1)) goto end; DBUG_ASSERT(bytes_read); @@ -561,7 +561,7 @@ static bool merge_walk(uchar *merge_buffer, size_t merge_buffer_size, /* save old_key not to overwrite it in read_to_buffer */ memcpy(save_key_buff, old_key, key_length); old_key= save_key_buff; - bytes_read= read_to_buffer(file, top, &sort_param); + bytes_read= read_to_buffer(file, top, &sort_param, false); if (unlikely(bytes_read == (ulong) -1)) goto end; else if (bytes_read) /* top->key, top->mem_count are reset */ @@ -609,7 +609,7 @@ static bool merge_walk(uchar *merge_buffer, size_t merge_buffer_size, top->advance_current_key(key_length); } while (top->decrement_mem_count()); - bytes_read= read_to_buffer(file, top, &sort_param); + bytes_read= read_to_buffer(file, top, &sort_param, false); if (unlikely(bytes_read == (ulong) -1)) goto end; } |