[HACKERS] To connect a debbuger...
Hello! I'm trying to add some features to PostgreSQL, but I just can't figure out how to make gdb work with it. I attach gdb to /usr/.../bin/postgres, then I put a breakpoint. Whenever postgres stop on that breakpoint, it just kills/restarts the server instead of asking me what to do. It's surely a noob's question but how can I use a debugger with PostegreSQL? Regards, Jonathan Scher (gdb) file /usr/local/pgsql/bin/postgres Reading symbols from /usr/local/pgsql/bin/postgres...(no debugging symbols found)...done. (gdb) set args -D /home/heziva/pgsql/pgsql_data/ (gdb) b transformFromClause Breakpoint 1 at 0x80e371e (gdb) r Starting program: /usr/local/pgsql/bin/postgres -D /home/heziva/pgsql/pgsql_data/ (no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...LOG: database system was interrupted; last known up at 2007-03-12 18:04:04 UTC LOG: checkpoint record is at 0/481504 LOG: redo record is at 0/481504; shutdown TRUE LOG: next transaction ID: 0/710; next OID: 16392 LOG: next MultiXactId: 1; next MultiXactOffset: 0 LOG: database system was not properly shut down; automatic recovery in progress LOG: record with zero length at 0/481544 LOG: redo is not required LOG: database system is ready to accept connections LOG: autovacuum launcher started = on another shell psql\d (gdb) file /usr/local/pgsql/bin/postgres Reading symbols from /usr/local/pgsql/bin/postgres...(no debugging symbols found)...done. (gdb) set args -D /home/heziva/pgsql/pgsql_data/ (gdb) b transformFromClause Breakpoint 1 at 0x80e371e (gdb) r Starting program: /usr/local/pgsql/bin/postgres -D /home/heziva/pgsql/pgsql_data/ (no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...LOG: database system was interrupted; last known up at 2007-03-12 18:04:04 UTC LOG: checkpoint record is at 0/481504 LOG: redo record is at 0/481504; shutdown TRUE LOG: next transaction ID: 0/710; next OID: 16392 LOG: next MultiXactId: 1; next MultiXactOffset: 0 LOG: database system was not properly shut down; automatic recovery in progress LOG: record with zero length at 0/481544 LOG: redo is not required LOG: database system is ready to accept connections LOG: autovacuum launcher started ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] CLUSTER, using SHARE UPDATE EXCLUSIVE lock?
That's lock upgrading, which opens you up to deadlocks. If another process grabs a lock after your update exclusive, you're not going to be able to upgrade it. OK I got the point. Is it possible to create a new table-level lock mode that says OK, now I'm on share level, but soon I will upgrade it to exclusive. Then it would be possible to allow any read-only operation, and to forbid all operation that would need to upgrade. I know that there is a sx_try_upgrade function on freeBSD kernel (man sx), so I guess there is a way to do it, isn't it? Regards, Jonathan Scher ---(end of broadcast)--- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
[HACKERS] UPSERT
Hello, I'd like to work on TODO item: Add REPLACE or UPSERT command that does UPDATE, or on failure, INSERT could you please tell me if I'm going in the right way? There are some different syntaxes possible, but MySQL has an interesting one here: http://dev.mysql.com/doc/refman/5.0/en/insert-on-duplicate.html INSERT INTO table (a,b,c) VALUES (1,2,3) ON DUPLICATE KEY UPDATE c=c+1; This allow to make an insert, and if the key is already there to modify the value depending on the current one. Then I have two choices possible: - Search for existing tuples among key or unique constraint, then if nothing is found, insert it. - Try to insert a new row, catch if there is any error, and then search for all tuple matching. As it would be a new command, I have no idea on what the data could be. Does syntax meet your needs? Which choice should I implement? Regards Jonathan Scher ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
[HACKERS] CLUSTER, using SHARE UPDATE EXCLUSIVE lock?
Hello, CLUSTER uses an ACCESS EXCLUSIVE lock. Why does it forbid concurrent reads? Florian G. Pflug, on a post ( http://archives.postgresql.org/pgsql-hackers/2007-02/msg00081.php ) suggested that there were no way to let the old entry until the command commit. I would like Cluster to create a new table, copying old values to this one, then delete the old one. This would allow Cluster to work with a share update exlusive lock, in order to allow reading the table while cluster is working. How does Cluster actually works? Why making a Cluster command less restrictive isn't even in the TO-list? Best regards, Jonathan Scher ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] CLUSTER, using SHARE UPDATE EXCLUSIVE lock?
Tom Lane a écrit : Jonathan Scher [EMAIL PROTECTED] writes: CLUSTER uses an ACCESS EXCLUSIVE lock. Why does it forbid concurrent reads? Because when it drops the old copy of the table there had better not be any concurrent readers. regards, tom lane Then, is it possible to take a share update exclusive lock until the new table is ready, then an access exclusive one only in order to switch tables? I don't think it's already coded like that... Regards Jonathan Scher ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
