This patch can be viewed as combination of two parts:
1) Enabling '-' in the path so that the parser does not give out a warning.
2) Setting the negative index to a correct value and returning the
appropriate value.
1) To enable using the negative index in the path:
To make the parser not return warning when negative index is used in path
'-' needs to be allowed in json path characters. P_NEG is added
to enable this and is made recognizable by setting the 45th index of
json_path_chr_map[] to P_NEG (instead of previous P_ETC)
because 45 corresponds to '-' in unicode.
When the path is being parsed and '-' is encountered, the parser should
recognize it as parsing '-' sign, so a new json state PS_NEG is required.
When the state is PS_NEG, it means that a negative integer is
going to be parsed so set is_negative_index of current step to 1 and
n_item is set accordingly when integer is encountered after '-'.
Next proceed with parsing rest of the path and get the correct path.
Next thing is parsing the json and returning correct value.
2) Setting the negative index to a correct value and returning the value:
While parsing json if we encounter array and the path step for the array
is a negative index (n_item < 0), then we can count the number of elements
in the array and set n_item to correct corresponding value. This is done in
json_skip_array_and_count.
Analysis: In case of error while processing json document, we goto
error label which eventually return 1 instead of 0.
Fix: Return 0 in case of error instead of 1.
1) When at least one of the two json documents is of scalar type:
1.a) If value and json document both are scalar, then return true
if they have same type and value.
1.b) If json document is scalar but other is array (or vice versa),
then return true if array has at least one element of same type
and value as scalar.
1.c) If one is scalar and other is object, then return false because
it can't be compared.
2) When both arguments are of non-scalar type and below conditons
are satisfied then return true:
2.a) When both arguments are arrays:
Iterate over the value and json document. If there exists at
least one element in other array of same type and value as
that of element in value.
2.b) If both arguments are objects:
Iterate over value and json document and if there exists at least
one key-value pair common between two objects.
2.c) If either of json document or value is array and other is object:
Iterate over the array, if an element of type object is found,
then compare it with the object (which is the other arguemnt).
If the entire object matches i.e all they key value pairs match.
Hybrid functions (IF, COALESCE, etc) did not preserve the JSON property
from their arguments. The same problem was repeatable for single row subselects.
The problem happened because the method Item::is_json_type() was inconsistently
implemented across the Item hierarchy. For example, Item_hybrid_func
and Item_singlerow_subselect did not override is_json_type().
Solution:
- Removing Item::is_json_type()
- Implementing specific JSON type handlers:
Type_handler_string_json
Type_handler_varchar_json
Type_handler_tiny_blob_json
Type_handler_blob_json
Type_handler_medium_blob_json
Type_handler_long_blob_json
- Reusing the existing data type infrastructure to pass JSON
type handlers across all item types, including classes Item_hybrid_func
and Item_singlerow_subselect. Note, these two classes themselves do not
need any changes!
- Extending the data type infrastructure so data types can inherit
their properties (e.g. aggregation rules) from their base data types.
E.g. VARCHAR/JSON acts as VARCHAR, LONGTEXT/JSON acts as LONGTEXT
when mixed to a non-JSON data type. This is done by:
- adding virtual method Type_handler::type_handler_base()
- adding a helper class Type_handler_pair
- refactoring Type_handler_hybrid_field_type methods
aggregate_for_result(), aggregate_for_min_max(),
aggregate_for_num_op() to use Type_handler_pair.
This change also fixes:
MDEV-27361 Hybrid functions with JSON arguments do not send format metadata
Also, adding mtr tests for JSON replication. It was not covered yet.
And the current patch changes the replication code slightly.
This patch implements JSON_EQUALS SQL function. The function takes
advantage of the json_normalize functionality and does the following:
norm_a = json_normalize(a)
norm_b = json_normalize(b)
return strcmp(norm_a, norm_b)
Co-authored-by: Vicențiu Ciorbaru <vicentiu@mariadb.org>
Revert "fix JSON_ARRAYAGG not to over-quote json in joins"
This removes 8711adb786 but keeps the test case.
A different fix is coming up.
Because args can be Item_field's that are later
replaced by Item_direct_view_ref to the actual field.
While Item_field preserved in orig_args will stay unfixed
with item->field==NULL and no metadata
use metadata (in particular is_json() property) of the original
argument item, even if the actual argument was later replaced
with an Item_temptable_field
Changes:
- To detect automatic strlen() I removed the methods in String that
uses 'const char *' without a length:
- String::append(const char*)
- Binary_string(const char *str)
- String(const char *str, CHARSET_INFO *cs)
- append_for_single_quote(const char *)
All usage of append(const char*) is changed to either use
String::append(char), String::append(const char*, size_t length) or
String::append(LEX_CSTRING)
- Added STRING_WITH_LEN() around constant string arguments to
String::append()
- Added overflow argument to escape_string_for_mysql() and
escape_quotes_for_mysql() instead of returning (size_t) -1 on overflow.
This was needed as most usage of the above functions never tested the
result for -1 and would have given wrong results or crashes in case
of overflows.
- Added Item_func_or_sum::func_name_cstring(), which returns LEX_CSTRING.
Changed all Item_func::func_name()'s to func_name_cstring()'s.
The old Item_func_or_sum::func_name() is now an inline function that
returns func_name_cstring().str.
- Changed Item::mode_name() and Item::func_name_ext() to return
LEX_CSTRING.
- Changed for some functions the name argument from const char * to
to const LEX_CSTRING &:
- Item::Item_func_fix_attributes()
- Item::check_type_...()
- Type_std_attributes::agg_item_collations()
- Type_std_attributes::agg_item_set_converter()
- Type_std_attributes::agg_arg_charsets...()
- Type_handler_hybrid_field_type::aggregate_for_result()
- Type_handler_geometry::check_type_geom_or_binary()
- Type_handler::Item_func_or_sum_illegal_param()
- Predicant_to_list_comparator::add_value_skip_null()
- Predicant_to_list_comparator::add_value()
- cmp_item_row::prepare_comparators()
- cmp_item_row::aggregate_row_elements_for_comparison()
- Cursor_ref::print_func()
- Removes String_space() as it was only used in one cases and that
could be simplified to not use String_space(), thanks to the fixed
my_vsnprintf().
- Added some const LEX_CSTRING's for common strings:
- NULL_clex_str, DATA_clex_str, INDEX_clex_str.
- Changed primary_key_name to a LEX_CSTRING
- Renamed String::set_quick() to String::set_buffer_if_not_allocated() to
clarify what the function really does.
- Rename of protocol function:
bool store(const char *from, CHARSET_INFO *cs) to
bool store_string_or_null(const char *from, CHARSET_INFO *cs).
This was done to both clarify the difference between this 'store' function
and also to make it easier to find unoptimal usage of store() calls.
- Added Protocol::store(const LEX_CSTRING*, CHARSET_INFO*)
- Changed some 'const char*' arrays to instead be of type LEX_CSTRING.
- class Item_func_units now used LEX_CSTRING for name.
Other things:
- Fixed a bug in mysql.cc:construct_prompt() where a wrong escape character
in the prompt would cause some part of the prompt to be duplicated.
- Fixed a lot of instances where the length of the argument to
append is known or easily obtain but was not used.
- Removed some not needed 'virtual' definition for functions that was
inherited from the parent. I added override to these.
- Fixed Ordered_key::print() to preallocate needed buffer. Old code could
case memory overruns.
- Simplified some loops when adding char * to a String with delimiters.
This was done to simplify copying of with_* flags
Other things:
- Changed Flags to C++ enums, which enables gdb to print
out bit values for the flags. This also enables compiler
errors if one tries to manipulate a non existing bit in
a variable.
- Added set_maybe_null() as a shortcut as setting the
MAYBE_NULL flags was used in a LOT of places.
- Renamed PARAM flag to SP_VAR to ensure it's not confused with persistent
statement parameters.
The reason for the change is that neither clang or gcc can do efficient
code when several bit fields are change at the same time or when copying
one or more bits between identical bit fields.
Updated bits explicitely with & and | is MUCH more efficient than what
current compilers can do.
Added back variable 'with_subquery' to Item class as a bit field.
This made the code shorter, faster (removed some virtual methods,
less code to create an initialized item etc) and made many Item's 7 bytes
smaller.
This is the last set of my patches the decreases the size of Item.
Some examples from gdb:
sizeof(Item): 144 -> 120
sizeof(Item_func) 208 -> 184
sizeof(Item_sum_max) 368 -> 344
The easiest way to compile and test the server with UBSAN is to run:
./BUILD/compile-pentium64-ubsan
and then run mysql-test-run.
After this commit, one should be able to run this without any UBSAN
warnings. There is still a few compiler warnings that should be fixed
at some point, but these do not expose any real bugs.
The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
memory access of integers. Fixed by using byte_order_generic.h when
compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
safe to have overflows (two cases, in item_func.cc).
Things fixed:
- Don't left shift signed values
(byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
constructors. This was needed as UBSAN checks that these types has
correct values when one copies an object.
(gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
deleted objects.
(events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
on Query_arena object.
- Fixed several cast of objects to an incompatible class!
(Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
This includes also ++ and -- of integers.
(Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
value_type is initialized to this instead of to -1, which is not a valid
enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.
- Fixed that Item_func_str::make_empty_result() creates an empty string
instead of a null string (safer as it ensures we do not do arithmetic
on null strings).
Other things:
- Changed struct st_position to an OBJECT and added an initialization
function to it to ensure that we do not copy or use uninitialized
members. The change to a class was also motived that we used "struct
st_position" and POSITION randomly trough the code which was
confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr. (This variable was before
only in 10.5 and up). It can now have one of two values:
ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
it virtual. This was an effort to get UBSAN to work with loaded storage
engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
in tabutil.cpp.
- Added HAVE_REPLICATION around usage of rgi_slave, to get embedded
server to compile with UBSAN. (Patch from Marko).
- Added #ifdef for powerpc64 to avoid a bug in old gcc versions related
to integer arithmetic.
Changes that should not be needed but had to be done to suppress warnings
from UBSAN:
- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
some compile time warnings.
Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes & Embedded server: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia
When first argument to the JSON_MERGE_PATCH was NULL and second - the
invalid JSON line, the error code was garbage. So it should be set to 0
initially.
Quick grouping is not supported for JSON_OBJECTAGG. The same for GROUP_CONCAT too
so make sure that Item::quick_group is set to FALSE. We need to make sure that in
the case of JSON_OBJECTAGG we don't create an index over grouping fields of
the temp table and update the result after each iteration.
Instead we should first sort the result in accordance to the
GROUP BY fields and then perform the grouping and
write the result to the temp table.
Item_func_json_extract did not implement val_decimal(),
so CAST(JSON_EXTRACT('{"x":true}', '$.x') AS DECIMAL) erroneously
returned 0 with a warning because of convertion from the string "true"
to decimal.
Implementing val_decimal(), so boolean values are correctly handled.
For DISTINCT to be handled with JSON_ARRAYAGG, we need to make sure
that the Unique tree also holds the NULL bytes of a table record
inside the node of the tree. This behaviour for JSON_ARRAYAGG is
different from GROUP_CONCAT because in GROUP_CONCAT we just reject
NULL values for columns.
Also introduced a comparator function for the unique tree to handle null
values for distinct inside JSON_ARRAYAGG.
We have to include NULL in the result which the GOUP_CONCAT doesn't
always do. Also converting should be done into another String instance
as these can be same.
