Fix mysql binary logging 0 parameters #5007
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Summary of Changes
Hello @zuofei, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!
This pull request resolves a bug in MySQL's binary logging mechanism. It ensures that when the system is configured to log zero parameters for prepared statements, the parameter count is correctly encoded and written to the binary log, preventing potential data integrity issues or misinterpretations in the log stream.
Highlights
- MySQL Binary Logging Fix: Corrected an issue in
MySQL_Event::write_query_format_1where the zero parameter count for prepared statements was not properly encoded into the buffer before being written to the binary log. This specifically addresses cases whereeventslog_stmt_parameters=0.
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Can one of the admins verify this patch? |
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Code Review
This pull request fixes an issue where MySQL query logging incorrectly handles zero prepared statement parameters. The change adds a call to write_encoded_length to ensure the number of parameters is correctly written to the log. A suggestion was made to initialize buf[0] before passing it to write_encoded_length to avoid using an uninitialized value.
| @@ -962,6 +962,7 @@ uint64_t MySQL_Event::write_query_format_1(std::fstream *f) { | |||
| // Deterministic binary logging: always report 0 parameters. | |||
| uint16_t num_params = 0; | |||
| uint8_t paramCountLen = mysql_encode_length(num_params, buf); | |||
| write_encoded_length(buf, num_params, paramCountLen, buf[0]); | |||
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The prefix argument in write_encoded_length is derived from buf[0], but buf[0] is not initialized in this branch. Although the code works correctly because len is 1, and prefix is unused when len==1, it's better to explicitly set buf[0] to num_params for clarity and to avoid potential issues if the function's logic changes in the future.
| write_encoded_length(buf, num_params, paramCountLen, buf[0]); | |
| buf[0] = (unsigned char)num_params; | |
| write_encoded_length(buf, num_params, paramCountLen, buf[0]); |
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add to whitelist |
Fix MySQL query logging zero prepared statement parameters when
eventslog_stmt_parameters=0