Re: [HACKERS] debugging tools inside postgres
On Fri, Jun 24, 2011 at 02:35:08PM +0800, HuangQi wrote: Hi, I'm trying to debug a modification for the query planner. But I found it seems the data structure of my planned query is incorrect. I was trying to print out the data structure by use the p command in gdb which is quite inconvenient and takes time. May I know is there any embedded function in postgres to print out the node data structures, or any other plan related data structures? Thanks. I don't know if anyone has done it, but recent versions of gdb apparenly can use python scripts, and use them to dump c++ library structures in readable formats. I guess someone could write some script to make debugging postgresql nicer (pretty printing snapshots, locks, etc). Have a nice day, -- Martijn van Oosterhout klep...@svana.org http://svana.org/kleptog/ Patriotism is when love of your own people comes first; nationalism, when hate for people other than your own comes first. - Charles de Gaulle signature.asc Description: Digital signature
Re: [HACKERS] debugging tools inside postgres
(2011/06/24 15:35), HuangQi wrote: Hi, I'm trying to debug a modification for the query planner. But I found it seems the data structure of my planned query is incorrect. I was trying to print out the data structure by use the p command in gdb which is quite inconvenient and takes time. May I know is there any embedded function in postgres to print out the node data structures, or any other plan related data structures? Thanks. I think nodeToString() would help. This function converts node tree recursively into a string, and it's applicable for any Node-derived object, such as Expr, Var and Const. ex) elog(DEBUG1, %s, nodeToString(plan)); Regards, -- Shigeru Hanada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] debugging tools inside postgres
2011/6/24 Shigeru Hanada shigeru.han...@gmail.com (2011/06/24 15:35), HuangQi wrote: Hi, I'm trying to debug a modification for the query planner. But I found it seems the data structure of my planned query is incorrect. I was trying to print out the data structure by use the p command in gdb which is quite inconvenient and takes time. May I know is there any embedded function in postgres to print out the node data structures, or any other plan related data structures? Thanks. I think nodeToString() would help. This function converts node tree recursively into a string, and it's applicable for any Node-derived object, such as Expr, Var and Const. ex) elog(DEBUG1, %s, nodeToString(plan)); Regards, -- Shigeru Hanada Hi, I don't know why but when I am debugging the query evaluation, the elog function can not output to shell. -- Best Regards Huang Qi Victor
Re: [HACKERS] debugging tools inside postgres
(2011/06/24 19:14), HuangQi wrote: 2011/6/24 Shigeru Hanadashigeru.han...@gmail.com (2011/06/24 15:35), HuangQi wrote: ex) elog(DEBUG1, %s, nodeToString(plan)); Hi, I don't know why but when I am debugging the query evaluation, the elog function can not output to shell. What kind of tool do you use to execute the query to be evaluated? If you are using an interactive tool such as psql, please check setting of client_min_messages. Otherwise, please check settings of log_destination, logging_collector and log_min_messages to ensure that elog() prints debugging information into your server log file, or stderr of the terminal which has been used to start PostgreSQL server. Regards, -- Shigeru Hanada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] debugging tools inside postgres
Shigeru Hanada shigeru.han...@gmail.com writes: (2011/06/24 15:35), HuangQi wrote: I'm trying to debug a modification for the query planner. But I found it seems the data structure of my planned query is incorrect. I was trying to print out the data structure by use the p command in gdb which is quite inconvenient and takes time. May I know is there any embedded function in postgres to print out the node data structures, or any other plan related data structures? Thanks. I think nodeToString() would help. For interactive use in gdb, I generally do call pprint(..node pointer..) which prints to the postmaster log. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] debugging tools inside postgres
On 24 June 2011 23:21, Tom Lane t...@sss.pgh.pa.us wrote: Shigeru Hanada shigeru.han...@gmail.com writes: (2011/06/24 15:35), HuangQi wrote: I'm trying to debug a modification for the query planner. But I found it seems the data structure of my planned query is incorrect. I was trying to print out the data structure by use the p command in gdb which is quite inconvenient and takes time. May I know is there any embedded function in postgres to print out the node data structures, or any other plan related data structures? Thanks. I think nodeToString() would help. For interactive use in gdb, I generally do call pprint(..node pointer..) which prints to the postmaster log. regards, tom lane Thanks, Tom, this call pprint() works very nice. -- Best Regards Huang Qi Victor
