MDEV-39412: parse error reading tabs in ranges#4994
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bsrikanth-mariadb wants to merge 1 commit intobb-12.3-MDEV-38805-dev-sprint-work-2from
Open
MDEV-39412: parse error reading tabs in ranges#4994bsrikanth-mariadb wants to merge 1 commit intobb-12.3-MDEV-38805-dev-sprint-work-2from
bsrikanth-mariadb wants to merge 1 commit intobb-12.3-MDEV-38805-dev-sprint-work-2from
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Note:
while reading from information_schema.optimizer_context one level of unescaping
is already done i.e. (\\t becomes \t or \\\\t becomes \\t)
w.r.t the MDEV, there are 2 problems: -
1.
When reading from the sql script file, json parser is not able to parse
the range value in json_read_value() from json_lib.c
"ranges": [
"(b\t\t\t\t\t\t) <= (b) <= (b???????)"
],
mainly the \t\t stuff, and hence a warning.
It also stops loading the context into memory.
Since, a new table is created with empty data, and without context,
we get Impossible WHERE noticed after reading const tables
2.
There is unescaping call being made in read_string() from sql_json_lib.cc
while parsing of the context. With this \\t was becoming \t.
However, print_range() from opt_range.cc already does escaping of the values.
The value "b\t\t\t" was in fact produced as "\b\\t\\t\\t".
Later, we try to compare range values from the query and the context.
Here a mismatch a found because, in one case there was escaping,
and in the other case escaping got removed.
Solutions
=========
For Problem 1. have escaping for ranges.
This should be done while dumping range values into the context.
For Problem 2. Remove unscaping call in read_string().
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Note:
while reading from information_schema.optimizer_context one level of unescaping is already done i.e. (\\t becomes \t or \\\\t becomes \\t)
w.r.t the MDEV, there are 2 problems: -
When reading from the sql script file, json parser is not able to parse the range value in json_read_value() from json_lib.c "ranges": [
"(b\t\t\t\t\t\t) <= (b) <= (b???????)"
],
mainly the \t\t stuff, and hence a warning.
It also stops loading the context into memory.
Since, a new table is created with empty data, and without context, we get Impossible WHERE noticed after reading const tables
There is unescaping call being made in read_string() from sql_json_lib.cc while parsing of the context. With this \\t was becoming \t. However, print_range() from opt_range.cc already does escaping of the values. The value "b\t\t\t" was in fact produced as "b\\t\\t\\t". Later, we try to compare range values from the query and the context.
Here a mismatch a found because, in one case there was escaping, and in the other case escaping got removed.
Solutions
For Problem 1. have escaping for ranges.
This should be done while dumping range values into the context.
For Problem 2. Remove unscaping call in read_string().