mirror of
https://github.com/MariaDB/server.git
synced 2025-08-26 01:44:06 +03:00
489ad44ab5
The code to get read the value of a system variable was extracting its value on PREPARE stage and was substituting the value (as a constant) into the parse tree. Note that this must be a reversible transformation, i.e. it must be reversed before each re-execution. Unfortunately this cannot be reliably done using the current code, because there are other non-reversible source tree transformations that can interfere with this reversible transformation. Fixed by not resolving the value at PREPARE, but at EXECUTE (as the rest of the functions operate). Added a cache of the value (so that it's constant throughout the execution of the query). Note that the cache also caches NULL values. Updated an obsolete related test suite (variables-big) and the code to test the result type of system variables (as per bug 74).