3736 magnus.blaudd@stripped 2012-04-25
WL#5906 read before write removal (RBWR)
- Adapt patch to latest trunk.
- Since both update and delete now does all the checks in one
place, the common code has been factored out into TABLE::check_read_removal() which is then
called both from mysql_update() and mysql_delete()
- Remove handler::read_before_write_removal_supported() in favor of using
the HA_READ_BEFORE_WRITE_REMOVAL table flag.
- Rename handler::read_before_write_removal_rows_written() to handler::end_read_removal()
- Rename handler::read_before_write_removal_possible() to handler::start_read_removal()
- Remove unnecessary DBUG printouts
modified:
sql/ha_ndbcluster.cc
sql/ha_ndbcluster.h
sql/handler.h
sql/sql_delete.cc
sql/sql_update.cc
sql/table.cc
sql/table.h
3735 magnus.blaudd@stripped 2012-04-25 [merge]
Merge trunk-wl5906 with trunk
modified:
sql/handler.h
sql/sql_delete.cc
sql/sql_update.cc
=== modified file 'sql/ha_ndbcluster.cc'
--- a/sql/ha_ndbcluster.cc 2012-03-28 11:25:37 +0000
+++ b/sql/ha_ndbcluster.cc 2012-04-25 12:30:33 +0000
@@ -7138,10 +7138,10 @@ int ha_ndbcluster::extra(enum ha_extra_f
}
-bool ha_ndbcluster::read_before_write_removal_possible()
+bool ha_ndbcluster::start_read_removal()
{
THD *thd= table->in_use;
- DBUG_ENTER("read_before_write_removal_possible");
+ DBUG_ENTER("start_read_removal");
if (uses_blob_value(table->write_set))
{
@@ -7188,9 +7188,10 @@ bool ha_ndbcluster::read_before_write_re
}
-ha_rows ha_ndbcluster::read_before_write_removal_rows_written(void) const
+ha_rows ha_ndbcluster::end_read_removal(void)
{
- DBUG_ENTER("read_before_write_removal_rows_written");
+ DBUG_ENTER("end_read_removal");
+ DBUG_ASSERT(m_read_before_write_removal_possible);
DBUG_PRINT("info", ("updated: %llu, deleted: %llu",
m_rows_updated, m_rows_deleted));
DBUG_RETURN(m_rows_updated + m_rows_deleted);
=== modified file 'sql/ha_ndbcluster.h'
--- a/sql/ha_ndbcluster.h 2012-03-28 11:25:37 +0000
+++ b/sql/ha_ndbcluster.h 2012-04-25 12:30:33 +0000
@@ -305,9 +305,8 @@ class ha_ndbcluster: public handler
#endif
void get_dynamic_partition_info(PARTITION_STATS *stat_info, uint part_id);
uint32 calculate_key_hash_value(Field **field_array);
- bool read_before_write_removal_supported() const { return true; }
- bool read_before_write_removal_possible();
- ha_rows read_before_write_removal_rows_written(void) const;
+ bool start_read_removal(void);
+ ha_rows end_read_removal(void);
int extra(enum ha_extra_function operation);
int extra_opt(enum ha_extra_function operation, ulong cache_size);
int reset();
=== modified file 'sql/handler.h'
--- a/sql/handler.h 2012-04-25 07:05:16 +0000
+++ b/sql/handler.h 2012-04-25 12:30:33 +0000
@@ -2169,27 +2169,23 @@ public:
virtual int extra_opt(enum ha_extra_function operation, ulong cache_size)
{ return extra(operation); }
- /**
- Informs handler that it is possible to optimize away the real read
- operation from the handler for the current table and instead
- use a generated read to optimze simple UPDATEs and DELETEs.
-
- @return true if handler supports rbwr for this write
+ /*
+ Start read (before write) removal on the current table. Fake rows may
+ be returned while reading from the selected index. This is used to
+ optimise simple UPDATE and DELETEs.The handler may refuse to start
+ due to internal limitations in the storage engine. Successful start
+ is always followed by end.
+ Function will only be called for handles who returns
+ HA_READ_BEFORE_WRITE_REMOVAL from table_flags()
*/
- virtual bool read_before_write_removal_possible(void)
- { return false; }
+ virtual bool start_read_removal(void)
+ { DBUG_ASSERT(0); return false; }
- /**
- Return the number of rows the handler has written while using
- read before write removal
-
- @return the number of rows actually written
- */
- virtual ha_rows read_before_write_removal_rows_written(void) const
- {
- DBUG_ASSERT(false);
- return (ha_rows) 0;
- }
+ /*
+ End read (before write) removal and return the number of rows really written
+ */
+ virtual ha_rows end_read_removal(void)
+ { DBUG_ASSERT(0); return (ha_rows) 0; }
/**
In an UPDATE or DELETE, if the row under the cursor was locked by another
=== modified file 'sql/sql_delete.cc'
--- a/sql/sql_delete.cc 2012-04-25 07:05:16 +0000
+++ b/sql/sql_delete.cc 2012-04-25 12:30:33 +0000
@@ -343,35 +343,13 @@ bool mysql_delete(THD *thd, TABLE_LIST *
else
will_batch= !table->file->start_bulk_delete();
- /*
- Read removal is possible if the selected quick read
- method is using full unique index
- */
- if (table->file->ha_table_flags() & HA_READ_BEFORE_WRITE_REMOVAL &&
- select && select->quick &&
- will_batch &&
- !thd->lex->ignore &&
- !using_limit)
- {
- const uint idx = select->quick->index;
- DBUG_PRINT("rbwr", ("checking index: %d", idx));
- const KEY *key= table->key_info + idx;
- if (key->flags & HA_NOSAME)
- {
- DBUG_PRINT("rbwr", ("index is unique"));
- bitmap_clear_all(&table->tmp_set);
- table->mark_columns_used_by_index_no_reset(idx, &table->tmp_set);
- if (bitmap_cmp(&table->tmp_set, table->read_set))
- {
- DBUG_PRINT("rbwr", ("using whole index, rbwr possible"));
- read_removal=
- table->file->read_before_write_removal_possible();
- }
- }
- }
-
table->mark_columns_needed_for_delete();
+ if ((table->file->ha_table_flags() & HA_READ_BEFORE_WRITE_REMOVAL) &&
+ !using_limit &&
+ select && select->quick && select->quick->index != MAX_KEY)
+ read_removal= table->check_read_removal(select->quick->index);
+
while (!(error=info.read_record(&info)) && !thd->killed &&
! thd->is_error())
{
@@ -434,9 +412,7 @@ bool mysql_delete(THD *thd, TABLE_LIST *
if (read_removal)
{
/* Only handler knows how many records were really written */
- DBUG_PRINT("rbwr", ("old deleted: %ld", (long)deleted));
- deleted= table->file->read_before_write_removal_rows_written();
- DBUG_PRINT("rbwr", ("really deleted: %ld", (long)deleted));
+ deleted= table->file->end_read_removal();
}
THD_STAGE_INFO(thd, stage_end);
end_read_record(&info);
=== modified file 'sql/sql_update.cc'
--- a/sql/sql_update.cc 2012-04-25 07:05:16 +0000
+++ b/sql/sql_update.cc 2012-04-25 12:30:33 +0000
@@ -474,35 +474,6 @@ int mysql_update(THD *thd,
}
} // Ends scope for optimizer trace wrapper
- /*
- Read removal is possible if the selected quick read
- method is using full unique index
-
- NOTE! table->read_set currently holds the columns which are
- used for the WHERE clause(this info is most likely already
- available in select->quick, but where?)
- */
- if (table->file->ha_table_flags() & HA_READ_BEFORE_WRITE_REMOVAL &&
- select && select->quick && select->quick->index != MAX_KEY &&
- !ignore &&
- !using_limit)
- {
- const uint idx= select->quick->index;
- DBUG_PRINT("rbwr", ("checking index: %d", idx));
- const KEY *key= table->key_info + idx;
- if (key->flags & HA_NOSAME)
- {
- DBUG_PRINT("rbwr", ("index is unique"));
- bitmap_clear_all(&table->tmp_set);
- table->mark_columns_used_by_index_no_reset(idx, &table->tmp_set);
- if (bitmap_cmp(&table->tmp_set, table->read_set))
- {
- DBUG_PRINT("rbwr", ("using full index, rbwr possible"));
- read_removal= true;
- }
- }
- }
-
/* If running in safe sql mode, don't allow updates without keys */
if (table->quick_keys.is_clear_all())
{
@@ -688,10 +659,6 @@ int mysql_update(THD *thd,
}
if (used_index < MAX_KEY && old_covering_keys.is_set(used_index))
table->set_keyread(false);
-
- /* Rows are already read -> not possible to remove */
- DBUG_PRINT("rbwr", ("rows are already read, turning off rbwr"));
- read_removal= false;
}
if (ignore)
@@ -730,13 +697,11 @@ int mysql_update(THD *thd,
else
will_batch= !table->file->start_bulk_update();
- if (read_removal &&
- will_batch &&
+ if ((table->file->ha_table_flags() & HA_READ_BEFORE_WRITE_REMOVAL) &&
+ !ignore && !using_limit &&
+ select && select->quick && select->quick->index != MAX_KEY &&
check_constant_expressions(values))
- {
- DBUG_ASSERT(select && select->quick);
- read_removal= table->file->read_before_write_removal_possible();
- }
+ read_removal= table->check_read_removal(select->quick->index);
// For prepare_record_for_error_message():
if (table->file->ha_table_flags() & HA_PARTIAL_COLUMN_READ)
@@ -952,15 +917,9 @@ int mysql_update(THD *thd,
if (read_removal)
{
/* Only handler knows how many records really was written */
- DBUG_PRINT("rbwr", ("adjusting updated: %ld, found: %ld",
- (long)updated, (long)found));
-
- updated= table->file->read_before_write_removal_rows_written();
+ updated= table->file->end_read_removal();
if (!records_are_comparable(table))
found= updated;
-
- DBUG_PRINT("rbwr", ("really updated: %ld, found: %ld",
- (long)updated, (long)found));
}
if (!transactional_table && updated > 0)
=== modified file 'sql/table.cc'
--- a/sql/table.cc 2012-04-18 13:06:39 +0000
+++ b/sql/table.cc 2012-04-25 12:30:33 +0000
@@ -5997,6 +5997,37 @@ Field *TABLE::get_timestamp_field()
}
+/*
+ Read removal is possible if the selected quick read
+ method is using full unique index
+
+ @param index Number of the index used for read
+
+ @retval true success, read removal started
+ @retval false read removal not started
+*/
+
+bool TABLE::check_read_removal(uint index)
+{
+ DBUG_ENTER("check_read_removal");
+ DBUG_ASSERT(file->ha_table_flags() & HA_READ_BEFORE_WRITE_REMOVAL);
+ DBUG_ASSERT(index != MAX_KEY);
+
+ // Index must be unique
+ if ((key_info[index].flags & HA_NOSAME) == 0)
+ DBUG_RETURN(false);
+
+ // Full index must be used
+ bitmap_clear_all(&tmp_set);
+ mark_columns_used_by_index_no_reset(index, &tmp_set);
+ if (!bitmap_cmp(&tmp_set, read_set))
+ DBUG_RETURN(false);
+
+ // Start read removal in handler
+ DBUG_RETURN(file->start_read_removal());
+}
+
+
/**
Test if the order list consists of simple field expressions
=== modified file 'sql/table.h'
--- a/sql/table.h 2012-04-16 09:26:56 +0000
+++ b/sql/table.h 2012-04-25 12:30:33 +0000
@@ -1157,6 +1157,8 @@ public:
Field *get_timestamp_field();
bool update_const_key_parts(Item *conds);
+
+ bool check_read_removal(uint index);
};
No bundle (reason: useless for push emails).
| Thread |
|---|
| • bzr push into mysql-trunk branch (magnus.blaudd:3735 to 3736) WL#5906 | magnus.blaudd | 25 Apr |
