The
[custom-engine.html#custom-engine-api-reference-index_read_idx
index_read_idx()
] method is identical to
[custom-engine.html#custom-engine-index-read
index_read()
] with the exception that
index_read_idx()
accepts an additional
keynr
parameter:
int ha_foo::index_read_idx(byte * buf, uint keynr, const byte * key,
ulonglong keypart_map,
enum ha_rkey_function find_flag)
The keynr
parameter specifies the index to be
read, as opposed to index_read()
, where the
index is already set.
As with the index_read()
method, the storage
engine must return the row that matches the key according to the
find_flag
and set a cursor for future reads.