Hi, I'd like to make it easier to analyze slow queries in ECPG using log_min_duration_statement. Especially when DBA and C application developer is different, DBA can feedback slow embedded query to the developer without difficulty and mistakes.
When our customers log and look into slower queries in C programs with embedded SQL, they use log_min_duration_statement.Using this logging option, SQL statement slower than a threshold will be displayed, but comments won't. That's because the pre-compiler (ECPG) removes all the comments when the pre-compiler converts C with embedded SQL to normal C code. Without comments, DBA has difficulty with identifying to which C code the slow query belongs. And the exact slow query issue cannot be reported to the developer. So, I'd like to modify ecpg command not to remove some specific comments. [Use-cases] Here is a scenario: 1) Writing comments to embedded C file a) Describe the detailed usage of SQL in each comment. b) Allocating id to each SQL. - application developer need to create corresponding table between id and the detailed description of SQL 2) DBA takes advantage of comments especially when: a) Similar comments are displayed here and there. In such a case, each comment plays a role as an identifier and makes it easier for DBA to identify SQL he/she looking for. b) DBA and C application developer are different. DBA can tell an application developer which query is slow without mistakes. [Interface] add a new option "--enable-parse-comment" to ecpg command. <usage> ecpg --enable-parse-comment ,..., prog.pgc This option enables ecpg command to pass on block comments (/* 〜 */) to converted C file. The conditions to enable processing "block comments" as follows: - a block comment can be used with SELECT, INSERT, UPDATE, or DELETE - a block comment can be placed right after keywords: SELECT, INSERT, UPDATE, DELETE or With - other than those above error will occur - line comment(--) are ignored, which is same as log output when logging libpq application [Example] 1)[Correct comment position] this comment position is right after SELECT EXEC SQL SELECT /* qid=3, at line 30 in yourApp.ecpg */ * INTO :C1, :C2 FROM T1 WHERE C1=1; 2)[Incorrect comment position] this comment position is bad（error will occur) EXEC SQL /* qid=3, at line 30 in yourApp.ecpg */ SELECT * INTO :C1, :C2 FROM T1 WHERE C1=1; As far as I searched, there seems no discussion on this topic. Please let me know if exists. Regards, Okano Naoki Fujitsu -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers