74 lines
2.0 KiB
PHP
74 lines
2.0 KiB
PHP
# ==== Purpose ====
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#
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# Execute a statement and compute the number of rows of the result set.
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#
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# This is intended to be used for queries like SHOW BINLOG EVENTS
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# where you cannot use COUNT(*). It would be nicer if mysqltest had
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# this feature. Now we have to execute the statement several times and
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# see if 'query_get_value(*, row) returns 'No such row'. Beware to not
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# use this for queries that have side effects.
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#
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# ==== Usage ====
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#
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# --let $statement= STATEMENT
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# --let $column= COLUMN_NAME
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# --source include/get_row_count.inc
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# --echo $statement has $row_count rows
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#
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# Parameters:
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# $statement
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# The statement to execute. Beware that this will be executed
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# multiple times.
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#
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# $column
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# The name of one column of the result. This may seem redundant
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# but unfortunately mysqltest forces you to specify a column name.
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#
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# Return value:
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# $row_count
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# The number of rows is stored in this variable.
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# Find upper bound on number of rows: check row numbers 1, 2, 4, 8, etc
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--let $_grc_max_row= 0
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--let $_grc_min_row= 0
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--let $_grc_row= 1
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while ($_grc_max_row == 0)
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{
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if ($rpl_debug)
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{
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--echo row=$_grc_row min_row=$_grc_min_row max_row=$_grc_max_row
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}
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--let $_grc_result= query_get_value($statement, $column, $_grc_row)
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if ($_grc_result == 'No such row')
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{
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--let $_grc_max_row= $_grc_row
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}
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if ($_grc_result != 'No such row')
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{
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--let $_grc_min_row= $_grc_row
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--let $_grc_row= `SELECT $_grc_row * 2`
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}
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}
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# Binary search to find exact count.
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while (`SELECT $_grc_min_row + 1 < $_grc_max_row`)
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{
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if ($rpl_debug)
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{
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--echo row=$_grc_row min_row=$_grc_min_row max_row=$_grc_max_row
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}
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--let $_grc_row= `SELECT ($_grc_min_row + $_grc_max_row) DIV 2`
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--let $_grc_result= query_get_value($statement, $column, $_grc_row)
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if ($_grc_result == 'No such row')
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{
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--let $_grc_max_row= $_grc_row
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}
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if ($_grc_result != 'No such row')
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{
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--let $_grc_min_row= $_grc_row
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}
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}
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# Store result
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--let $row_count= $_grc_min_row
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