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WL#2126 - Multi_read_range.

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Added the required structures and functions for
handing over multiple key ranges to the table handler.
This commit is contained in:
ingo@mysql.com
2004-12-23 21:45:10 +01:00
parent bf40ab8cb1
commit 60e35755ef
9 changed files with 406 additions and 68 deletions
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125
sql/handler.cc
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@ -1685,6 +1685,131 @@ int ha_table_exists(THD* thd, const char* db, const char* name)
#endif
/*
Read the first row of a multi-range set.
SYNOPSIS
read_multi_range_first()
found_range_p Returns a pointer to the element in 'ranges' that
corresponds to the returned row.
ranges An array of KEY_MULTI_RANGE range descriptions.
range_count Number of ranges in 'ranges'.
sorted If result should be sorted per key.
buffer A HANDLER_BUFFER for internal handler usage.
NOTES
Record is read into table->record[0].
*found_range_p returns a valid value only if read_multi_range_first()
returns 0.
Sorting is done within each range. If you want an overall sort, enter
'ranges' with sorted ranges.
RETURN
0 OK, found a row
HA_ERR_END_OF_FILE No rows in range
# Error code
*/
int handler::read_multi_range_first(KEY_MULTI_RANGE **found_range_p,
KEY_MULTI_RANGE *ranges, uint range_count,
bool sorted, HANDLER_BUFFER *buffer)
{
int result= HA_ERR_END_OF_FILE;
DBUG_ENTER("handler::read_multi_range_first");
multi_range_sorted= sorted;
multi_range_buffer= buffer;
for (multi_range_curr= ranges, multi_range_end= ranges + range_count;
multi_range_curr < multi_range_end;
multi_range_curr++)
{
result= read_range_first(multi_range_curr->start_key.length ?
&multi_range_curr->start_key : 0,
multi_range_curr->end_key.length ?
&multi_range_curr->end_key : 0,
test(multi_range_curr->range_flag & EQ_RANGE),
multi_range_sorted);
if (result != HA_ERR_END_OF_FILE)
break;
}
*found_range_p= multi_range_curr;
DBUG_PRINT("exit",("result %d", result));
DBUG_RETURN(result);
}
/*
Read the next row of a multi-range set.
SYNOPSIS
read_multi_range_next()
found_range_p Returns a pointer to the element in 'ranges' that
corresponds to the returned row.
NOTES
Record is read into table->record[0].
*found_range_p returns a valid value only if read_multi_range_next()
returns 0.
RETURN
0 OK, found a row
HA_ERR_END_OF_FILE No (more) rows in range
# Error code
*/
int handler::read_multi_range_next(KEY_MULTI_RANGE **found_range_p)
{
int result;
DBUG_ENTER("handler::read_multi_range_next");
/* We should not be called after the last call returned EOF. */
DBUG_ASSERT(multi_range_curr < multi_range_end);
do
{
/* Save a call if there can be only one row in range. */
if (multi_range_curr->range_flag != (UNIQUE_RANGE | EQ_RANGE))
{
result= read_range_next();
/* On success or non-EOF errors jump to the end. */
if (result != HA_ERR_END_OF_FILE)
break;
}
else
{
/*
We need to set this for the last range only, but checking this
condition is more expensive than just setting the result code.
*/
result= HA_ERR_END_OF_FILE;
}
/* Try the next range(s) until one matches a record. */
for (multi_range_curr++;
multi_range_curr < multi_range_end;
multi_range_curr++)
{
result= read_range_first(multi_range_curr->start_key.length ?
&multi_range_curr->start_key : 0,
multi_range_curr->end_key.length ?
&multi_range_curr->end_key : 0,
test(multi_range_curr->range_flag & EQ_RANGE),
multi_range_sorted);
if (result != HA_ERR_END_OF_FILE)
break;
}
}
while ((result == HA_ERR_END_OF_FILE) &&
(multi_range_curr < multi_range_end));
*found_range_p= multi_range_curr;
DBUG_PRINT("exit",("handler::read_multi_range_next: result %d", result));
DBUG_RETURN(result);
}
/*
Read first row between two ranges.
Store ranges for future calls to read_range_next