Skip to content

M
mariadb
Commit 0bedf4d9 authored by marko's avatar marko
Browse files
Options

Reduce the size of btr_search_t from 13 machine words to 7. This 

structure is reserved for every index in the data dictionary cache.
(Bug #20877)

We could shrink the structure further to three 32-bit words or two
64-bit words by turning the remaining fields to bit-fields.
Unfortunately, the fields are not protected by any mutex, and thus we
would better keep each field aligned to a machine word.

btr_search_t, buf_block_t: Rename "ulint side" to "ibool left_side".
Remove BTR_SEARCH_LEFT_SIDE and BTR_SEARCH_RIGHT_SIDE, and also rename
some local variables and function parameters from "ulint side" to
"ibool left_side".

btr_search_t: Remove the unused fields last_search, n_direction, direction,
and modify_clock.  Remove the unused constants BTR_SEA_NO_DIRECTION,
BTR_SEA_LEFT, BTR_SEA_RIGHT, and BTR_SEA_SAME_REC.

btr_search_t: Remove magic_n unless #defined UNIV_DEBUG.  Turn an assertion
about the magic number into a debug assertion.
parent adcb90a0
Show whitespace changes
Inline Side-by-side
Showing with 61 additions and 84 deletions
btr/btr0sea.c
View file @ 0bedf4d9
......@@ -74,7 +74,7 @@ btr_search_build_page_hash_index(
ulint n_fields,/* in: hash this many full fields */
ulint n_bytes,/* in: hash this many bytes from the next
field */
ulint side); /* in: hash for searches from this side */
ibool left_side);/* in: hash for searches from left side? */
/*********************************************************************
This function should be called before reserving any btr search mutex, if
......@@ -157,10 +157,10 @@ btr_search_info_create(
info = mem_heap_alloc(heap, sizeof(btr_search_t));
#ifdef UNIV_DEBUG
info->magic_n = BTR_SEARCH_MAGIC_N;
#endif /* UNIV_DEBUG */
info->last_search = NULL;
info->n_direction = 0;
info->root_guess = NULL;
info->hash_analysis = 0;
......@@ -179,7 +179,7 @@ btr_search_info_create(
info->n_fields = 1;
info->n_bytes = 0;
info->side = BTR_SEARCH_LEFT_SIDE;
info->left_side = TRUE;
return(info);
}
......@@ -224,7 +224,7 @@ btr_search_info_update_hash(
hash prefix */
if (info->n_fields >= n_unique && cursor->up_match >= n_unique) {
increment_potential:
info->n_hash_potential++;
return;
......@@ -233,8 +233,7 @@ btr_search_info_update_hash(
cmp = ut_pair_cmp(info->n_fields, info->n_bytes,
cursor->low_match, cursor->low_bytes);
if ((info->side == BTR_SEARCH_LEFT_SIDE && cmp <= 0)
|| (info->side == BTR_SEARCH_RIGHT_SIDE && cmp > 0)) {
if (info->left_side ? cmp <= 0 : cmp > 0) {
goto set_new_recomm;
}
......@@ -242,16 +241,11 @@ btr_search_info_update_hash(
cmp = ut_pair_cmp(info->n_fields, info->n_bytes,
cursor->up_match, cursor->up_bytes);
if ((info->side == BTR_SEARCH_LEFT_SIDE && cmp > 0)
|| (info->side == BTR_SEARCH_RIGHT_SIDE && cmp <= 0)) {
if (info->left_side ? cmp <= 0 : cmp > 0) {
goto set_new_recomm;
goto increment_potential;
}
info->n_hash_potential++;
return;
set_new_recomm:
/* We have to set a new recommendation; skip the hash analysis
for a while to avoid unnecessary CPU time usage when there is no
......@@ -269,7 +263,7 @@ set_new_recomm:
info->n_fields = 1;
info->n_bytes = 0;
info->side = BTR_SEARCH_LEFT_SIDE;
info->left_side = TRUE;
} else if (cmp > 0) {
info->n_hash_potential = 1;
......@@ -288,7 +282,7 @@ set_new_recomm:
info->n_bytes = cursor->low_bytes + 1;
}
info->side = BTR_SEARCH_LEFT_SIDE;
info->left_side = TRUE;
} else {
info->n_hash_potential = 1;
......@@ -306,7 +300,7 @@ set_new_recomm:
info->n_bytes = cursor->up_bytes + 1;
}
info->side = BTR_SEARCH_RIGHT_SIDE;
info->left_side = FALSE;
}
}
......@@ -336,18 +330,18 @@ btr_search_update_block_hash_info(
info->last_hash_succ = FALSE;
ut_a(block->magic_n == BUF_BLOCK_MAGIC_N);
ut_a(info->magic_n == BTR_SEARCH_MAGIC_N);
ut_ad(info->magic_n == BTR_SEARCH_MAGIC_N);
if ((block->n_hash_helps > 0)
&& (info->n_hash_potential > 0)
&& (block->n_fields == info->n_fields)
&& (block->n_bytes == info->n_bytes)
&& (block->side == info->side)) {
&& (block->left_side == info->left_side)) {
if ((block->is_hashed)
&& (block->curr_n_fields == info->n_fields)
&& (block->curr_n_bytes == info->n_bytes)
&& (block->curr_side == info->side)) {
&& (block->curr_left_side == info->left_side)) {
/* The search would presumably have succeeded using
the hash index */
......@@ -360,7 +354,7 @@ btr_search_update_block_hash_info(
block->n_hash_helps = 1;
block->n_fields = info->n_fields;
block->n_bytes = info->n_bytes;
block->side = info->side;
block->left_side = info->left_side;
}
#ifdef UNIV_DEBUG
......@@ -378,7 +372,7 @@ btr_search_update_block_hash_info(
> 2 * page_get_n_recs(block->frame))
|| (block->n_fields != block->curr_n_fields)
|| (block->n_bytes != block->curr_n_bytes)
|| (block->side != block->curr_side)) {
|| (block->left_side != block->curr_left_side)) {
/* Build a new hash index on the page */
......@@ -422,7 +416,7 @@ btr_search_update_hash_ref(
&& (info->n_hash_potential > 0)
&& (block->curr_n_fields == info->n_fields)
&& (block->curr_n_bytes == info->n_bytes)
&& (block->curr_side == info->side)) {
&& (block->curr_left_side == info->left_side)) {
mem_heap_t* heap = NULL;
ulint offsets_[REC_OFFS_NORMAL_SIZE];
*offsets_ = (sizeof offsets_) / sizeof *offsets_;
......@@ -512,7 +506,7 @@ btr_search_info_update_slow(
params = mem_alloc(3 * sizeof(ulint));
params[0] = block->n_fields;
params[1] = block->n_bytes;
params[2] = block->side;
params[2] = block->left_side;
/* Make sure the compiler cannot deduce the values and do
optimizations */
......@@ -1102,7 +1096,7 @@ btr_search_build_page_hash_index(
ulint n_fields,/* in: hash this many full fields */
ulint n_bytes,/* in: hash this many bytes from the next
field */
ulint side) /* in: hash for searches from this side */
ibool left_side)/* in: hash for searches from left side? */
{
hash_table_t* table;
buf_block_t* block;
......@@ -1136,7 +1130,7 @@ btr_search_build_page_hash_index(
if (block->is_hashed && ((block->curr_n_fields != n_fields)
|| (block->curr_n_bytes != n_bytes)
|| (block->curr_side != side))) {
|| (block->curr_left_side != left_side))) {
rw_lock_s_unlock(&btr_search_latch);
......@@ -1191,7 +1185,7 @@ btr_search_build_page_hash_index(
fold = rec_fold(rec, offsets, n_fields, n_bytes, tree_id);
if (side == BTR_SEARCH_LEFT_SIDE) {
if (left_side) {
folds[n_cached] = fold;
recs[n_cached] = rec;
......@@ -1203,7 +1197,7 @@ btr_search_build_page_hash_index(
if (page_rec_is_supremum(next_rec)) {
if (side == BTR_SEARCH_RIGHT_SIDE) {
if (!left_side) {
folds[n_cached] = fold;
recs[n_cached] = rec;
......@@ -1221,7 +1215,7 @@ btr_search_build_page_hash_index(
if (fold != next_fold) {
/* Insert an entry into the hash index */
if (side == BTR_SEARCH_LEFT_SIDE) {
if (left_side) {
folds[n_cached] = next_fold;
recs[n_cached] = next_rec;
......@@ -1243,7 +1237,7 @@ btr_search_build_page_hash_index(
if (block->is_hashed && ((block->curr_n_fields != n_fields)
|| (block->curr_n_bytes != n_bytes)
|| (block->curr_side != side))) {
|| (block->curr_left_side != left_side))) {
goto exit_func;
}
......@@ -1252,7 +1246,7 @@ btr_search_build_page_hash_index(
block->curr_n_fields = n_fields;
block->curr_n_bytes = n_bytes;
block->curr_side = side;
block->curr_left_side = left_side;
block->index = index;
for (i = 0; i < n_cached; i++) {
......@@ -1291,7 +1285,7 @@ btr_search_move_or_delete_hash_entries(
buf_block_t* new_block;
ulint n_fields;
ulint n_bytes;
ulint side;
ibool left_side;
block = buf_block_align(page);
new_block = buf_block_align(new_page);
......@@ -1319,22 +1313,23 @@ btr_search_move_or_delete_hash_entries(
n_fields = block->curr_n_fields;
n_bytes = block->curr_n_bytes;
side = block->curr_side;
left_side = block->curr_left_side;
new_block->n_fields = block->curr_n_fields;
new_block->n_bytes = block->curr_n_bytes;
new_block->side = block->curr_side;
new_block->left_side = left_side;
rw_lock_s_unlock(&btr_search_latch);
ut_a(n_fields + n_bytes > 0);
btr_search_build_page_hash_index(index, new_page, n_fields,
n_bytes, side);
n_bytes, left_side);
#if 1 /* TODO: safe to remove? */
ut_a(n_fields == block->curr_n_fields);
ut_a(n_bytes == block->curr_n_bytes);
ut_a(side == block->curr_side);
ut_a(left_side == block->curr_left_side);
#endif
return;
}
......@@ -1428,7 +1423,7 @@ btr_search_update_hash_node_on_insert(
if ((cursor->flag == BTR_CUR_HASH)
&& (cursor->n_fields == block->curr_n_fields)
&& (cursor->n_bytes == block->curr_n_bytes)
&& (block->curr_side == BTR_SEARCH_RIGHT_SIDE)) {
&& !block->curr_left_side) {
table = btr_search_sys->hash_index;
......@@ -1465,7 +1460,7 @@ btr_search_update_hash_on_insert(
ulint next_fold = 0; /* remove warning (??? bug ???) */
ulint n_fields;
ulint n_bytes;
ulint side;
ibool left_side;
ibool locked = FALSE;
mem_heap_t* heap = NULL;
ulint offsets_[REC_OFFS_NORMAL_SIZE];
......@@ -1495,7 +1490,7 @@ btr_search_update_hash_on_insert(
n_fields = block->curr_n_fields;
n_bytes = block->curr_n_bytes;
side = block->curr_side;
left_side = block->curr_left_side;
ins_rec = page_rec_get_next(rec);
next_rec = page_rec_get_next(ins_rec);
......@@ -1516,7 +1511,7 @@ btr_search_update_hash_on_insert(
n_fields + (n_bytes > 0), &heap);
fold = rec_fold(rec, offsets, n_fields, n_bytes, tree_id);
} else {
if (side == BTR_SEARCH_LEFT_SIDE) {
if (left_side) {
rw_lock_x_lock(&btr_search_latch);
......@@ -1537,7 +1532,7 @@ btr_search_update_hash_on_insert(
locked = TRUE;
}
if (side == BTR_SEARCH_RIGHT_SIDE) {
if (!left_side) {
ha_insert_for_fold(table, fold, rec);
} else {
ha_insert_for_fold(table, ins_fold, ins_rec);
......@@ -1547,7 +1542,7 @@ btr_search_update_hash_on_insert(
check_next_rec:
if (page_rec_is_supremum(next_rec)) {
if (side == BTR_SEARCH_RIGHT_SIDE) {
if (!left_side) {
if (!locked) {
rw_lock_x_lock(&btr_search_latch);
......@@ -1570,7 +1565,7 @@ check_next_rec:
locked = TRUE;
}
if (side == BTR_SEARCH_RIGHT_SIDE) {
if (!left_side) {
ha_insert_for_fold(table, ins_fold, ins_rec);
/*
......@@ -1680,7 +1675,7 @@ btr_search_validate(void)
(void*) page, (ulong) block->is_hashed,
(ulong) block->curr_n_fields,
(ulong) block->curr_n_bytes,
(ulong) block->curr_side);
(ulong) block->curr_left_side);
if (n_page_dumps < 20) {
buf_page_print(page);
......
buf/buf0buf.c
View file @ 0bedf4d9
......@@ -1583,7 +1583,7 @@ buf_page_init_for_backup_restore(
block->is_hashed = FALSE;
block->n_fields = 1;
block->n_bytes = 0;
block->side = BTR_SEARCH_LEFT_SIDE;
block->left_side = TRUE;
block->file_page_was_freed = FALSE;
}
......@@ -1650,7 +1650,7 @@ buf_page_init(
block->is_hashed = FALSE;
block->n_fields = 1;
block->n_bytes = 0;
block->side = BTR_SEARCH_LEFT_SIDE;
block->left_side = TRUE;
block->file_page_was_freed = FALSE;
}
......
include/btr0sea.h
View file @ 0bedf4d9
......@@ -134,48 +134,34 @@ btr_search_validate(void);
/*======================*/
/* out: TRUE if ok */
/* Search info directions */
#define BTR_SEA_NO_DIRECTION 1
#define BTR_SEA_LEFT 2
#define BTR_SEA_RIGHT 3
#define BTR_SEA_SAME_REC 4
/* The search info struct in an index */
struct btr_search_struct{
ulint magic_n; /* magic number */
/* The following 4 fields are currently not used: */
rec_t* last_search; /* pointer to the lower limit record of the
previous search; NULL if not known */
ulint n_direction; /* number of consecutive searches in the
same direction */
ulint direction; /* BTR_SEA_NO_DIRECTION, BTR_SEA_LEFT,
BTR_SEA_RIGHT, BTR_SEA_SAME_REC,
or BTR_SEA_SAME_PAGE */
dulint modify_clock; /* value of modify clock at the time
last_search was stored */
/*----------------------*/
/* The following 4 fields are not protected by any latch: */
/* The following fields are not protected by any latch.
Unfortunately, this means that they must be aligned to
the machine word, i.e., they cannot be turned into bit-fields. */
page_t* root_guess; /* the root page frame when it was last time
fetched, or NULL */
ulint hash_analysis; /* when this exceeds a certain value, the
hash analysis starts; this is reset if no
ulint hash_analysis; /* when this exceeds BTR_SEARCH_HASH_ANALYSIS,
the hash analysis starts; this is reset if no
success noticed */
ibool last_hash_succ; /* TRUE if the last search would have
succeeded, or did succeed, using the hash
index; NOTE that the value here is not exact:
it is not calculated for every search, and the
calculation itself is not always accurate! */
ulint n_hash_potential;/* number of consecutive searches which would
have succeeded, or did succeed, using the hash
index */
ulint n_hash_potential;
/* number of consecutive searches
which would have succeeded, or did succeed,
using the hash index;
the range is 0 .. BTR_SEARCH_BUILD_LIMIT + 5 */
/*----------------------*/
ulint n_fields; /* recommended prefix length for hash search:
number of full fields */
ulint n_bytes; /* recommended prefix: number of bytes in
an incomplete field */
ulint side; /* BTR_SEARCH_LEFT_SIDE or
BTR_SEARCH_RIGHT_SIDE, depending on whether
an incomplete field;
cf. BTR_PAGE_MAX_REC_SIZE */
ibool left_side; /* TRUE or FALSE, depending on whether
the leftmost record of several records with
the same prefix should be indexed in the
hash index */
......@@ -188,10 +174,12 @@ struct btr_search_struct{
far */
ulint n_searches; /* number of searches */
#endif /* UNIV_SEARCH_PERF_STAT */
#ifdef UNIV_DEBUG
ulint magic_n; /* magic number */
# define BTR_SEARCH_MAGIC_N 1112765
#endif /* UNIV_DEBUG */
};
#define BTR_SEARCH_MAGIC_N 1112765
/* The hash index system */
typedef struct btr_search_sys_struct btr_search_sys_t;
......@@ -229,9 +217,6 @@ is no hope in building a hash index. */
#define BTR_SEARCH_HASH_ANALYSIS 17
#define BTR_SEARCH_LEFT_SIDE 1
#define BTR_SEARCH_RIGHT_SIDE 2
/* Limit of consecutive searches for trying a search shortcut on the search
pattern */
......
include/buf0buf.h
View file @ 0bedf4d9
......@@ -825,8 +825,7 @@ struct buf_block_struct{
search: number of full fields */
ulint n_bytes; /* recommended prefix: number of bytes
in an incomplete field */
ulint side; /* BTR_SEARCH_LEFT_SIDE or
BTR_SEARCH_RIGHT_SIDE, depending on
ibool left_side; /* TRUE or FALSE, depending on
whether the leftmost record of several
records with the same prefix should be
indexed in the hash index */
......@@ -851,9 +850,7 @@ struct buf_block_struct{
ulint curr_n_fields; /* prefix length for hash indexing:
number of full fields */
ulint curr_n_bytes; /* number of bytes in hash indexing */
ulint curr_side; /* BTR_SEARCH_LEFT_SIDE or
BTR_SEARCH_RIGHT_SIDE in hash
indexing */
ibool curr_left_side; /* TRUE or FALSE in hash indexing */
dict_index_t* index; /* Index for which the adaptive
hash index has been created. */
/* 6. Debug fields */
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7