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Fixes for condition pushdown to storage engine based on comments from code review

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mysql-test/r/ndb_condition_pushdown.result:
  Added more tests  for condition pushdown to storage engine based on comments from code review
mysql-test/t/ndb_condition_pushdown.test:
  Added more tests  for condition pushdown to storage engine based on comments from code review
This commit is contained in:
unknown
2005-02-23 15:51:26 +01:00
parent a2bb52c748
commit 9968b41dbf
6 changed files with 489 additions and 301 deletions
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48
sql/handler.h
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@ -451,7 +451,7 @@ public:
enum {NONE=0, INDEX, RND} inited;
bool auto_increment_column_changed;
bool implicit_emptied; /* Can be !=0 only if HEAP */
const COND *pushed_cond;
handler(TABLE *table_arg) :table(table_arg),
ref(0), data_file_length(0), max_data_file_length(0), index_file_length(0),
@ -460,7 +460,8 @@ public:
create_time(0), check_time(0), update_time(0),
key_used_on_scan(MAX_KEY), active_index(MAX_KEY),
ref_length(sizeof(my_off_t)), block_size(0),
raid_type(0), ft_handler(0), inited(NONE), implicit_emptied(0)
raid_type(0), ft_handler(0), inited(NONE), implicit_emptied(0),
pushed_cond(NULL)
{}
virtual ~handler(void) { /* TODO: DBUG_ASSERT(inited == NONE); */ }
int ha_open(const char *name, int mode, int test_if_locked);
@ -724,23 +725,34 @@ public:
Condition pushdown to storage engines
*/
/*
Push a condition to storage engine for evaluation during table
and index scans. The conditions should be stored on a stack
for possibly storing several conditions. The stack can be popped
by calling cond_pop, handler::extra(HA_EXTRA_RESET) (handler::reset())
should clear the stack.
The condition can be traversed using Item::traverse_cond
RETURN
NULL The condition was supported by the handler and will be evaluated
for each row found during the scan
cond The condition was not supported and all rows will be returned from
the scan for evaluation (and thus not saved on stack)
*/
/*
Push condition down to the table handler.
SYNOPSIS
cond_push()
cond Condition to be pushed. The condition tree must not be
modified by the by the caller.
RETURN
The 'remainder' condition that caller must use to filter out records.
NULL means the handler will not return rows that do not match the
passed condition.
NOTES
The pushed conditions form a stack (from which one can remove the
last pushed condition using cond_pop).
The table handler filters out rows using (pushed_cond1 AND pushed_cond2
AND ... AND pushed_condN)
or less restrictive condition, depending on handler's capabilities.
handler->extra(HA_EXTRA_RESET) call empties the condition stack.
Calls to rnd_init/rnd_end, index_init/index_end etc do not affect the
condition stack.
*/
virtual const COND *cond_push(const COND *cond) { return cond; };
/*
Pop the top condition from the condition stack of the handler instance.
*/
/*
Pop the top condition from the condition stack of the handler instance.
SYNOPSIS
cond_pop()
Pops the top if condition stack, if stack is not empty
*/
virtual void cond_pop() { return; };
};