Since the whole preparable statement will be available, it is
superfluous to provide a function using which the operation of
the preparable statement can be obtained.
This function will return the preparable statement of a PREPARE
statement as a COM_QUERY GWBUF. That is, once obtained, the normal
query classifier functions can be used for obtaining information
about the preparable statement itself.
- Only types of fixed size used in API interface
- The actual function return value specifies whether the parsing
process succeeded, while "logical" return values are returned
as out arguments.
The wrapper function currently ignores the function return value.
The setting up and the initialization of the query classifier has
now been separated. The gateway explicitly sets up the query
classifier (i.e. chooses which one to use and what arguments to
provide), but the actual initialization is performed as part of
the general module initialization.
Together with the field names, now qc_get_field_info also returns
field usage information, that is, in what context a field is used.
This allows, for instance, the cache to take action if a a particular
field is selected (SELECT a FROM ...), but not if it is used in a
GROUP BY clause (...GROUP BY a).
This caused a significant modifications of qc_mysqlembedded that
earlier did not walk the parse-tree, but instead looped over of a
list of st_select_lex instances that, the name notwithstanding,
also contain information about other things but SELECTs. The former
approach lost all contextual information, so it was not possible
to know where a particular field was used.
Now the parse tree is walked, which means that the contextual
information is known, and thus the field usage can be updated.
Function is no longer used and it was quite unoptimal, so now
removed.
qc_get_prepare_name, qc_get_prepare_operation and qc_get_field_info
that were missing from qc_dummy added at the same time.
This function returns more detailed information about the fields
of a statement. Supersedes qc_get_affected_fields() that will
be deprecated and removed.
Note that this function now introduced new kind of behaviour; the
returned data belongs to the GWBUF and remains valid for as long as
the GWBUF is alive. That means that unnecessary copying need not
be done.
The operation of the statement to be prepared is no longer
reported as the operation of the PREPARE statement.
Instead, when the type of the statement is
QUERY_TYPE_PREPARE_NAMED_STMT, the operation can be obtained
using qc_get_prepare_operation().
The qc_mysqlembedded implementation will be provided in a
subsequent commit.
- STRERROR_BUFLEN moved to cdefs.h and renamed to MXS_STRERROR_BUFLEN.
Better would be to provide a 'const char* mxs_strerror(int errno)'
that would have a thread specific buffer for the error message.
- MIN and MAX also moved to defs.h as MXS_MIN and MXS_MAX.
- Now only mlist.h of the headers depend upon skygw_utils.h.
- All now include maxscale/cdefs.h as the very first file.
- MXS_[BEGIN|END]_DECLS added to all C-headers.
Strictly speaking not necessary for private headers, but
does not hurt either.
- Include guards moved to the very top of the file.
- #pragma once added.
- Headers now to be included as <maxscale/xyz.h>
- First step, no cleanup of headers has been made. Only moving
from one place to another + necessary modifications.
