Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
Requiring contiguous buffers removes the need to use mxs::Buffer which
also removes the need to check for buffer boundaries.
Converted all the functions used by get_canonical into `static inline` so
that the compiler knows it can inline them. A few of them weren't `static`
which made the calls to the functions unnecessarily expensive.
The backslash was added instead of assigned. Since the value stored at
that position is always a null byte, assignment and addition would result
in the same outcome.
A GWBUF given to any gwbuf-function:
- Must not be NULL. Exceptions are gwbuf_free() and gwbuf_append(),
in analogy with free() and realloc() respectively.
- Must be the head of a chain.
- Must be owned by the calling thread.
The process of appending to a std::string always includes a size check in
case the internal storage needs to expand. Given that we know a
canonicalized version of a query string is never larger than the original
string and that we pre-allocate enough memory to cope with the worst-case
scenario, the extra logic in std::string::push_back is unnecessary and an
extra cost. Writing directly into the string avoids this cost and improves
the performance.
Switched from default character type functions to ones that use lookup
tables. Eliminated the internal state and replaced with in-place iteration
of the query. Added code to allow single-lookup detection of normal
characters.
Since we know the worst-case size of a canonical statement is the size of
the query string, we can reduce the number of memory allocations to one in
the get_canonical function.
Replaced SPINLOCK with std::mutex where possible, leaving out the more
complex cases. The big offenders remaining are the binlogrouter and the
gateway.cc OpenSSL locks.
See script directory for method. The script to run in the top level
MaxScale directory is called maxscale-uncrustify.sh, which uses
another script, list-src, from the same directory (so you need to set
your PATH). The uncrustify version was 0.66.
The resultset processing for MySQL requires some extra work as it lacks
the proper SERVER_MORE_RESULTS_EXIST flag in the last EOF packet. Instead,
the first EOF packet has the SERVER_PS_OUT_PARAMS flag which needs to be
interpreted as a SERVER_MORE_RESULTS_EXIST flag for the second EOF packet.
Also corrected the EOF packet handling to do the flag checks in the code
that deals with the EOF packets.
As the modutil_state parameter is now used for more than large packet
tracking, the correct solution is to store this state object in the
readwritesplit session instead of interpreting it to a boolean value.
Readwritesplit would not handle multiple overlapping COM_STMT_EXECUTE
commands properly if they opened cursors. This was due to the fact that
the result would not be marked as complete and COM_STMT_FETCH commands
were executed as if they did not return results.
The correct implementation is to consider a COM_STMT_EXECUTE that opens a
cursor complete only when the first EOF packet is read (that is, when the
resultset header is read). This allows subsequent COM_STMT_FETCH commands
to be handled separately.
The separate COM_STMT_FETCH handling must count the number of packets that
are being fetched. This allows correct tracking of the state of a
COM_STMT_FETCH by checking that the number of packets is correct or the
second EOF/ERR packet is read.
The canonicalization process now strips non-executable comments from the
SQL and replaces all constants in executable comments.
Enabled the comment test and updated expected output of the select and
alter tests.
Updated tests with new expected output. Also took new function into use
and removed the old one.
Since the comment removal isn't added yet, one of the tests is expected to
fail and it is temporarily disabled.
