Hi, Aleksey! On Mar 11, Aleksey Midenkov wrote:
Hi, Sergei!
ha_partition::handle_ordered_index_scan() stores records in m_ordered_rec_buffer. Then TABLE::update_virtual_fields() updates blob buffer and frees the old one. Then ha_partition::return_top_record() returns record from m_ordered_rec_buffer with stale blob pointer. What should we do with this? I propose to duplicate blob buffer when record gets into m_ordered_rec_buffer.
You can make Field_blob to forget that it owns the buffer. And when reading back from the queue, Field_blob will need to take over the buffer again. It's String::release() and String::reset() methods. The tricky part here is that Field_blob doesn't always own the buffer, sometimes the storage engine does. So, when reading from the queue and restoring the ownership you'll need to take care to do it only for values that Field_blob used to own before, not for all blobs. Regards, Sergei Chief Architect MariaDB and security@mariadb.org