Re: [HACKERS] Problem with PITR recovery
Hi Simon, Actually, me too. Never saw the need for the Oracle command myself. It actually has. If you want to move your redo logs to a new disk, you create a new redo log file and then issue a ALTER SYSTEM SWITCH LOGFILE; to switch to the new logfile. Then you can remove the old one (speaking just of one file for simplification). Waiting on that event could take ages. Strictly speaking, this doesn't concern postgresql (yet). But if, at the future, we support user defined (= changing these parameters while the db is running) redo log locations, sizes and count, we need a function to switch the logfile manually. Which I think the pg_stop_backup() hack is not suitable for. ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
Re: [HACKERS] About b-tree usage
Hi, if you're using a pg version prio to 8.0 your pitfall might also be a conversion between int and bigint datatypes. So if you're doing somthing like SELECT a.x, b.y, c.y FROM a, b WHERE a.x = b.x; and a.x is INT4 and b.x is INT8 (or BIGINT) the planner counts this as a data conversion and uses a full table scan. Greetings, Klaus Ioannis Theoharis wrote: let me, i have turned enable_seqscan to off, in order to discourage optimizer to choose seq_scan whenever an idex_scan can be used. But in this case, why optimizer don't chooses seq_scan (discourage is different than prevent) ? At many cases i need only a small fragment of raws to be retrieved. But this extreme case is a real-scenario (not the most frequent but real). I try to find a way to achieve good performence even for the extreme case. Is there any way? ps. In bibliografy, there is a different alternative for indices. except th simple approach of attr_val, rid is the alternative attr_val, set of rids. The second means the attaches to each discrete attr_val the set o rid's of all raws with same attr_val. Is this alternative taken into account in postgres? On Mon, 7 Mar 2005, Jeff Davis wrote: In that case, sequential scan is faster, but perhaps the planner doesn't know that ahead of time. Try turning on more statistics if you haven't already, and then run ANALYZE again. If the planner sees a range, perhaps it assumes that it is a highly selective range, when in fact, it consists of all of the tuples. Also, make sure enable_seqscan is true (in case you turned it off for testing or something and forgot). A seqscan is usually faster when a large proportion of the tuples are returned because: (1) It uses sequential I/O; whereas an index might access tuples in a random order. (2) It doesn't have to read the index's disk pages at all. I suspect you don't need to return all the tuples in the table. If you include the details of a real scenario perhaps the people on the list could be more helpful. ---(end of broadcast)--- TIP 3: 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 ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] Hi ...Inheritance in postgres 7.3.4 reg.
On Thu, 22 Jul 2004, K-Sudhakaran wrote: Hi Sudhakaran, I'm not sure if I missunderstand you, but I think the feature you're describing is foreign keys ... If it's not, please try to describe it in more detail. Greeetings, Klaus Hi/Hello Postgres Team! Me Sudhakaran, working for a software RD institution located in Bangalore city of India. I feel that, if a table (entity) inherits another parent table(entity), the primary key should be unique accross all the inherited tables. That is the real inheritance otherwise I feel it is a mere containment of structure what we have in postgres 7.3.4. Because, say for example, as in my application domain, if a staff member inherits citizen, it means that, when a staff instance is added to staff entity, then it takes role in citizen (its parent) entity by default as after all every staff is a citizen. I am interested in contributing for this effort's special feature. Can I know which source code files I may have 2 explore to understand the Inheritance implementation in postgres 7.3.4 which I am using right now in my application development. Hope you would encourage me going ahead in this open source way of getting wanted things, by your postive response out of your bussy schedules. Thanx a lot. Kind regards K.Sudhakaran K.Sudhakaran Staff Scientist #68 National Centre for Software Technology Electronic City,Hosur Road Bangalore. 561 229 Phone. 8523300 Extn 2404 Love all Serve All Help Ever , Hurt Never ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html -- Full Name : Klaus Naumann | (http://www.mgnet.de/) (Germany) Phone / FAX : ++49/177/7862964 | E-Mail: ([EMAIL PROTECTED]) ---(end of broadcast)--- TIP 3: 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] User Quota Implementation
On Thu, 8 Jul 2004, Jonah H. Harris wrote: Hi, 3. The maximum quota size is (currently) the maximum of int4*1024 bytes. why is this? This is very limiting ... Using a 64bit value would be a lot more straight foreward. Greetings, Klaus -- Full Name : Klaus Naumann | (http://www.mgnet.de/) (Germany) Phone / FAX : ++49/177/7862964 | E-Mail: ([EMAIL PROTECTED]) ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
Re: [HACKERS] User Quota Implementation
On Fri, 9 Jul 2004, Stephen Frost wrote: Hi, why is this? This is very limiting ... It's 2TB... Yeah, you're right. I didn't take into account, that you multiply it with 1kb - my fault. 2TB is enough - at the moment at least. But implementing it in 64 from now on could save a lot of work in the future ... It sounded to me like it might be a limitation forced by some other part of postgres, but I don't really know... Good question though. I'm not sure about it either - anyone? Greetings, Klaus -- Full Name : Klaus Naumann | (http://www.mgnet.de/) (Germany) Phone / FAX : ++49/177/7862964 | E-Mail: ([EMAIL PROTECTED]) ---(end of broadcast)--- TIP 8: explain analyze is your friend
