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ovsdb: optimize match_any_clause() condition evaluation
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Optimize ovsdb_condition_match_any_clause() to be in O(#columns in condition)
and not O(#clauses) in case condition's caluses function is boolean or "==".

Signed-off-by: Liran Schour <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>
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@liranschour @blp
liranschour authored and blp committed Jul 19, 2016
1 parent 845a118 commit f0d7ae1
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Showing 5 changed files with 125 additions and 10 deletions.
114 changes: 113 additions & 1 deletion ovsdb/condition.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -192,6 +192,69 @@ compare_clauses_3way_with_data(const void *a_, const void *b_)
&a->column->type);
}

struct ovsdb_o_column {
const struct ovsdb_column *column;
struct hmap o_clauses;
};

struct ovsdb_o_clause {
struct ovsdb_datum *arg;
struct hmap_node hmap_node;
};

static void
ovsdb_condition_optimize(struct ovsdb_condition *cnd)
{
size_t i;
uint32_t hash;

if (!cnd->optimized) {
return;
}

for(i = 0; i < cnd->n_clauses; i++) {
struct ovsdb_clause *clause = &cnd->clauses[i];

if (clause->function != OVSDB_F_EQ) {
continue;
}

struct ovsdb_o_clause *o_clause = xzalloc(sizeof *o_clause);
struct ovsdb_o_column *o_column =
shash_find_data(&cnd->o_columns, clause->column->name);

if (!o_column) {
o_column = xzalloc(sizeof *o_column);
o_column->column = clause->column;
hmap_init(&o_column->o_clauses);
shash_add(&cnd->o_columns, clause->column->name, o_column);
}
o_clause->arg = &clause->arg;
hash = ovsdb_datum_hash(&clause->arg, &clause->column->type, 0);
hmap_insert(&o_column->o_clauses, &o_clause->hmap_node, hash);
}
}

static void
ovsdb_condition_optimize_destroy(struct ovsdb_condition *cnd)
{
struct shash_node *node, *next;

SHASH_FOR_EACH_SAFE (node, next, &cnd->o_columns) {
struct ovsdb_o_column *o_column = node->data;
struct ovsdb_o_clause *c, *c_next;

HMAP_FOR_EACH_SAFE(c, c_next, hmap_node, &o_column->o_clauses) {
hmap_remove(&o_column->o_clauses, &c->hmap_node);
free(c);
}
hmap_destroy(&o_column->o_clauses);
shash_delete(&cnd->o_columns, node);
free(o_column);
}
shash_destroy(&cnd->o_columns);
}

struct ovsdb_error *
ovsdb_condition_from_json(const struct ovsdb_table_schema *ts,
const struct json *json,
Expand All @@ -201,8 +264,9 @@ ovsdb_condition_from_json(const struct ovsdb_table_schema *ts,
const struct json_array *array = json_array(json);
size_t i;

ovsdb_condition_init(cnd);
cnd->clauses = xmalloc(array->n * sizeof *cnd->clauses);
cnd->n_clauses = 0;

for (i = 0; i < array->n; i++) {
struct ovsdb_error *error;
error = ovsdb_clause_from_json(ts, array->elems[i], symtab,
Expand All @@ -214,12 +278,17 @@ ovsdb_condition_from_json(const struct ovsdb_table_schema *ts,
return error;
}
cnd->n_clauses++;
if (cnd->clauses[i].function > OVSDB_F_EQ) {
cnd->optimized = false;
}
}

/* A real database would have a query optimizer here. */
qsort(cnd->clauses, cnd->n_clauses, sizeof *cnd->clauses,
compare_clauses_3way_with_data);

ovsdb_condition_optimize(cnd);

return NULL;
}

Expand Down Expand Up @@ -352,6 +421,34 @@ ovsdb_condition_match_every_clause(const struct ovsdb_row *row,
return true;
}

static bool
ovsdb_condition_match_any_clause_optimized(const struct ovsdb_datum *row_datum,
const struct ovsdb_condition *cnd,
unsigned int index_map[])
{
if (ovsdb_condition_is_true(cnd)) {
return true;
}

struct shash_node *node;
SHASH_FOR_EACH (node, &cnd->o_columns) {
struct ovsdb_o_column *o_column = node->data;
const struct ovsdb_column *column = o_column->column;
const struct ovsdb_datum *arg = &row_datum[index_map ?
index_map[column->index] :
column->index];
uint32_t hash = ovsdb_datum_hash(arg, &column->type, 0);
struct ovsdb_o_clause *o_clause;

HMAP_FOR_EACH_WITH_HASH(o_clause, hmap_node, hash, &o_column->o_clauses) {
if (ovsdb_datum_equals(arg, o_clause->arg, &column->type)) {
return true;
}
}
}
return false;
}

/* Returns true if condition evaluation of one of the clauses is
* true. index_map[] is an optional array that if exists indicates a mapping
* between indexing row_datum to the indexes in ovsdb_column */
Expand All @@ -362,6 +459,11 @@ ovsdb_condition_match_any_clause(const struct ovsdb_datum *row_datum,
{
size_t i;

if (cnd->optimized) {
return ovsdb_condition_match_any_clause_optimized(row_datum, cnd,
index_map);
}

for (i = 0; i < cnd->n_clauses; i++) {
if (ovsdb_clause_evaluate(row_datum, &cnd->clauses[i], index_map)) {
return true;
Expand All @@ -381,13 +483,17 @@ ovsdb_condition_destroy(struct ovsdb_condition *cnd)
}
free(cnd->clauses);
cnd->n_clauses = 0;

ovsdb_condition_optimize_destroy(cnd);
}

void
ovsdb_condition_init(struct ovsdb_condition *cnd)
{
cnd->clauses = NULL;
cnd->n_clauses = 0;
cnd->optimized = true;
shash_init(&cnd->o_columns);
}

bool
Expand Down Expand Up @@ -424,12 +530,18 @@ ovsdb_condition_clone(struct ovsdb_condition *to,
{
size_t i;

ovsdb_condition_init(to);

to->clauses = xzalloc(from->n_clauses * sizeof *to->clauses);

for (i = 0; i < from->n_clauses; i++) {
ovsdb_clause_clone(&to->clauses[i], &from->clauses[i]);
}
to->n_clauses = from->n_clauses;
to->optimized = from->optimized;
if (to->optimized) {
ovsdb_condition_optimize(to);
}
}

/* Return true if ovsdb_condition_match_any_clause() will return true on
Expand Down
5 changes: 4 additions & 1 deletion ovsdb/condition.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,9 +62,12 @@ struct ovsdb_clause {
struct ovsdb_condition {
struct ovsdb_clause *clauses;
size_t n_clauses;
bool optimized;
struct shash o_columns;
};

#define OVSDB_CONDITION_INITIALIZER { NULL, 0}
#define OVSDB_CONDITION_INITIALIZER(COND) \
{ NULL, 0, true, SHASH_INITIALIZER(&(COND)->o_columns)}

void ovsdb_condition_init(struct ovsdb_condition *);
bool ovsdb_condition_empty(const struct ovsdb_condition *);
Expand Down
10 changes: 5 additions & 5 deletions ovsdb/execution.c
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Original file line number Diff line number Diff line change
Expand Up @@ -352,7 +352,7 @@ ovsdb_execute_select(struct ovsdb_execution *x, struct ovsdb_parser *parser,
{
struct ovsdb_table *table;
const struct json *where, *columns_json, *sort_json;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
struct ovsdb_column_set sort = OVSDB_COLUMN_SET_INITIALIZER;
struct ovsdb_error *error;
Expand Down Expand Up @@ -420,7 +420,7 @@ ovsdb_execute_update(struct ovsdb_execution *x, struct ovsdb_parser *parser,
{
struct ovsdb_table *table;
const struct json *where, *row_json;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
struct ovsdb_row *row = NULL;
struct update_row_cbdata ur;
Expand Down Expand Up @@ -494,7 +494,7 @@ ovsdb_execute_mutate(struct ovsdb_execution *x, struct ovsdb_parser *parser,
struct ovsdb_table *table;
const struct json *where;
const struct json *mutations_json;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct ovsdb_mutation_set mutations = OVSDB_MUTATION_SET_INITIALIZER;
struct ovsdb_row *row = NULL;
struct mutate_row_cbdata mr;
Expand Down Expand Up @@ -551,7 +551,7 @@ ovsdb_execute_delete(struct ovsdb_execution *x, struct ovsdb_parser *parser,
{
struct ovsdb_table *table;
const struct json *where;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct ovsdb_error *error;

where = ovsdb_parser_member(parser, "where", OP_ARRAY);
Expand Down Expand Up @@ -606,7 +606,7 @@ ovsdb_execute_wait(struct ovsdb_execution *x, struct ovsdb_parser *parser,
{
struct ovsdb_table *table;
const struct json *timeout, *where, *columns_json, *until, *rows;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
struct ovsdb_row_hash expected = OVSDB_ROW_HASH_INITIALIZER(expected);
struct ovsdb_row_hash actual = OVSDB_ROW_HASH_INITIALIZER(actual);
Expand Down
2 changes: 1 addition & 1 deletion ovsdb/monitor.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -688,7 +688,7 @@ ovsdb_monitor_table_condition_update(
struct ovsdb_monitor_table_condition *mtc =
shash_find_data(&condition->tables, table->schema->name);
struct ovsdb_error *error;
struct ovsdb_condition cond = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition cond = OVSDB_CONDITION_INITIALIZER(&cond);

if (!condition) {
return NULL;
Expand Down
4 changes: 2 additions & 2 deletions ovsdb/replication.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -535,7 +535,7 @@ execute_delete(struct ovsdb_txn *txn, const char *uuid,
{
const struct json *where;
struct ovsdb_error *error;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
char where_string[UUID_LEN+29];

if (!table) {
Expand Down Expand Up @@ -586,7 +586,7 @@ execute_update(struct ovsdb_txn *txn, const char *uuid,
struct ovsdb_table *table, struct json *json_row)
{
struct ovsdb_column_set columns = OVSDB_COLUMN_SET_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER;
struct ovsdb_condition condition = OVSDB_CONDITION_INITIALIZER(&condition);
struct update_row_cbdata ur;
struct ovsdb_row *row;
struct ovsdb_error *error;
Expand Down

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