Fwd: [HACKERS] Double linked list with one pointer [mendola@bigfoot.com]
I could see how this would work if you always had a reference to one of the nodes. The problem with the approach I can see is that you *have* to always know the value of at least one pointer, and maintaining that will ultimately require more coding than just having two pointers. Assume CurrentNode is a pointer to on element in the list: CurrentNode = some node in the list // This node knows what one of the pointers is. List *TempNode = CurrentNode // This node does not know what one of the pointers is because it was never told. So, TempNode can't traverse the list. Like I say, passing the known pointer value around would take more coding than maintaining two pointers in the list. Richard Schilling - Begin Forwarded Message - Date: 2003.12.06 08:03 Subject: [HACKERS] Double linked list with one pointer From: Gaetano Mendola [EMAIL PROTECTED] To: [EMAIL PROTECTED] [EMAIL PROTECTED] Message-ID: [EMAIL PROTECTED] If I'm not wrong Neil Conway is working on reimplement a double linked list. Looking around I found this post of Herb Sutter on comp.lang.c++: In particular, a motivation behind two-way pointers is that you can have a more space-efficient doubly linked list if you store only one (not two) pointer's worth of storage in each node. But how can the list still be traversable in both directions? The idea is that each node stores, not a pointer to one other node, but a pointer to the previous node XOR'd with a pointer to the next node. To traverse the list in either direction, at each node you get a pointer to the next node by simply XORing the current node's two-way pointer value with the address of the last node you visited, which yields the address of the next node you want to visit. For more details, see: Running Circles Round You, Logically by Steve Dewhurst C/C++ Users Journal (20, 6), June 2002 I don't think the article is available online, alas, but you can find some related source code demonstrating the technique at: http://www.semantics.org/tyr/tyr0_5/list.h = In this way we are going to save a pointer for each node, what do you think ? Regards Gaetano Mendola ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings - End Forwarded Message - ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [HACKERS] Commercial binary support?
On 2003.11.19 14:17 Austin Gonyou wrote: All, I sincerely apologize for possibly starting a flame war, I wasn't aware this might be a hot-button issue. Hopefully some good will come of it none-the-less, like others who come after me might see the reasons our db application developers want this type of go to support. No need to apologize Austin. Let me answer your post also, even though I'm posting late. We do provide binary support for PostgreSQL and any other open source product we support even though we don't push it in advertising. When all is said and done we're only distributing patched binaries and following the changes to the code base. The trick in providing binary support is that under our current business model (cheap, standardized hourly rate), the customer needs to understand that they are paying us for our time to apply patches, do code reviews, coding etc ... it's not like a product you get from Oracle where the cost of maintenance is amortized over all the customers. The benefit to this approach, however is that our customers get exactly the changes they want - they actually drive features development by having us improve the base product for their specific needs. Richard Schilling ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] postmaster startup failure
I ran into this too. Patched the code with Tom's change and it works fine. Thanks again Tom! Richard Schilling On 2003.07.17 11:04 Hannu Krosing wrote: Tom Lane kirjutas N, 17.07.2003 kell 19:49: Ugh. The reason we hadn't seen this happen in the field was that it is a bug I introduced in a patch two months ago :-( 7.3.3 will in fact fail to start up, with the above error, any time the last record of the WAL file ends exactly at a page boundary. I think we're gonna need a quick 7.3.4 ... If you want a source patch for 7.3.3, here it is. Thanks! --- Hannu ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [HACKERS] [pgsql-advocacy] Announcement: planned open source billing system demonstration now available
I'll be posting the license on our website soon. But, the license for our original work, prior to an Open Source release, is an open source license except that the end user cannot distribute the product beyond their immediate control (e.g. their company). And, the changes one client makes to the product becomes available to all the other clients. It's kind of like an open source license that applies just to our clients. The only restriction really is non-distribution. If/when a software product gets released under and open source license we incorporate the changes that clients have made to customize the product prior to release. So, if we have 20 customers using the same product and they've had customizations done. It's working out pretty well. We're using this model for the software we built for http://www.thenew-hometeam.com. So, yes, the mature version of the home listing search engine we built will eventually be released under a general open source license. Richard Schilling On 2003.09.23 18:15 Ruben Safir Secretary NYLXS wrote: And what is the licensing? On Tue, Sep 23, 2003 at 06:06:00PM -0700, Richard Schilling wrote: Just wanted to drop you all a quick note that CogBilling, an online billing system which integrates with GnuCash, is now available for review at http://www.rsmba.biz/download. CogBilling is an online database driven billing system written entirely on open source products. In its present state it's intentionally void of heavy graphic images and creature features to maximize flexibility in developing future versions. CogBilling is intended to be useful for any professional services organization, but ultimately should function especially well in organizations that do software development, legal services and the like. Furthermore, CogBilling is intended to be integrated into large IT infrastructures such as those found in healthcare institutions, clinics and physician practices. This application is the first public release of our planned open source applications. Once we can sustain continuous development of the application through the sale of services and website hosting we will release the whole thing under a traditional open source license (e.g. Gnu, BSD, etc . . .). At the present, we expect this to occur in the spring or summer of 2004. For the more technically inclined, CogBilling was written in Embedded Perl (Embperl), and uses a PostgreSQL database as the backend. It is hosted on the latest version of the Apache web server. This is the first beta release of the product, so the user interface promises to be a bit rough, and the online manual is not presently available. However, you will find that the system's basic functionality works. Future directions we have planned with this product is deeper integration with GnuCash at the database level, integration with GnoTime, and integration with Issue Tracker. You can e-mail me directly, but for the benefit of the Open Source community you should also post comments, criticisms or suggestions posted to this discussion list. Thank you. Richard Schilling - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- __ Brooklyn Linux Solutions __ DRM is THEFT - We are the STAKEHOLDERS http://fairuse.nylxs.com http://www.mrbrklyn.com - Consulting http://www.inns.net -- Happy Clients http://www.nylxs.com - Leadership Development in Free Software http://www2.mrbrklyn.com/resources - Unpublished Archive or stories and articles from around the net http://www2.mrbrklyn.com/downtown.html - See the New Downtown Brooklyn 1-718-382-0585 ---(end of broadcast)--- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
[HACKERS] Announcement: planned open source billing system demonstration now available
Just wanted to drop you all a quick note that CogBilling, an online billing system which integrates with GnuCash, is now available for review at http://www.rsmba.biz/download. CogBilling is an online database driven billing system written entirely on open source products. In its present state it's intentionally void of heavy graphic images and creature features to maximize flexibility in developing future versions. CogBilling is intended to be useful for any professional services organization, but ultimately should function especially well in organizations that do software development, legal services and the like. Furthermore, CogBilling is intended to be integrated into large IT infrastructures such as those found in healthcare institutions, clinics and physician practices. This application is the first public release of our planned open source applications. Once we can sustain continuous development of the application through the sale of services and website hosting we will release the whole thing under a traditional open source license (e.g. Gnu, BSD, etc . . .). At the present, we expect this to occur in the spring or summer of 2004. For the more technically inclined, CogBilling was written in Embedded Perl (Embperl), and uses a PostgreSQL database as the backend. It is hosted on the latest version of the Apache web server. This is the first beta release of the product, so the user interface promises to be a bit rough, and the online manual is not presently available. However, you will find that the system's basic functionality works. Future directions we have planned with this product is deeper integration with GnuCash at the database level, integration with GnoTime, and integration with Issue Tracker. You can e-mail me directly, but for the benefit of the Open Source community you should also post comments, criticisms or suggestions posted to this discussion list. Thank you. Richard Schilling ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [HACKERS] DBD::Pg, schema support
Can you give an example on how to execute that command? I've been wondering about that too but haven't had time to read the documentation. Richard On 2003.07.23 10:30 [EMAIL PROTECTED] wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 is't possible to specify default search path for dbh in DBD::Pg ? I don't want to set variable before every select. There is nothing specific to DBD::Pg, but you should be able to issue the command once (SET search_path...) and have all subsequent requests on the same database handle use that schema. - -- Greg Sabino Mullane [EMAIL PROTECTED] PGP Key: 0x14964AC8 200307231328 -BEGIN PGP SIGNATURE- Comment: http://www.turnstep.com/pgp.html iD8DBQE/HsXXvJuQZxSWSsgRArfEAJ4+mIE7fTXnvf3JHS2Y3WmSoZwO/QCgxpx0 RuTjTUI3hngy2T9BMqDEXpE= =tvul -END PGP SIGNATURE- ---(end of broadcast)--- TIP 8: explain analyze is your friend ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster
[HACKERS] RFP announcement
A few weeks ago I posted a message on this board requesting interest from anyone who would be willing to participate in a Request For Proposal (RFP) to provide software development and project management for Washington State. I am happy to announce that we have several dozen participants at present. Everyone who has responded has been added to the list of participants, and will now be reviewing the actual RFP. If you have not gotten any e-mails regarding this project, but wanted to be on the distribution list, please inform me immediately and we'll get you added. I'm very excited about the possibility of working with this community on such a project. Please contact me if you have any questions. Richard Schilling Proprietor National Informatics Company ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [HACKERS] Need help for our thesis.
As luck would have I've put some thought into this problem before as well. Having reviewed the code quite a bit, and played around with the backend, my intuition tells me that the following would work. Write a custom cluster-aware postmaster so it distributes queries to various machines. Of course each machine would have to be running a normal postmaster to receive the queries. And, the cluster-aware postmaster would need to be informed of which machines to submit queries to (e.g. listed in a configuration file). Queries could be processed in the following ways: * database management queries (e.g. create database, create table, alter table, etc. . . ) would be distributed to every machine * select queries would be distributed to every machine. The cluster-aware postmaster would merge the results before delivering them to the client. * an insert query would go to one machine only, and the cluster-aware postmaster could switch between the designated machines after each insert. For example, given two machines, the first insert would go to machine A, the second to machine B, etc . . . Don't know if that's been tried, but that's where I would start. Postgres' modular design of a postmaster and a backend would make this relatively easy to do, because the only thing you might end up writing is the one cluster-aware postmaster. If you end up doing this let me know and if I have time I'll help out with the design/coding. Richard Schilling Lake Stevens, WA USA On 2003.07.04 18:56 MIka Santos wrote: Gud day! We are currently having our thesis for our undergarduate course and this involoves the code of PostgreSQL. Basically, our thesis needs a modification of the existing code of the said database. As of now, our University has an existing online registration system which uses Postgre as their back end. But the problem is the existing one is not a distributed system. Our thesis adviser would like us to deal with the load balancing of the said online registration. He wanted a multidatabase querying. For example, we knew that the following statements are posible, select * from t1, t2., t3; provided that t1 and t2, t3 are tables from a single database. Our thesis is to make the following satatement legal select * from d1, d2, d3; provided that d1 and d2, d3 are separate databases. We are currently having our research about this problem and as beginners, we surely need help from experts like you. Any form of comments and suggestions will surely be appreciated by the group. Thank you very much and hope to here from you. - Do you Yahoo!? Free online calendar with sync to Outlook(TM). ---(end of broadcast)--- TIP 7: don't forget to increase your free space map settings
[HACKERS] contract opportunity for the willing.
Just wanted to announce that for those interested I'm looking at submitting an RFP to Washington State (in the US). Being PostgreSQL is my database of choice I would like to invite anyone who is interested and has PostgreSQL programming/administration experience to contact me. Backend database work will be crucial on this work, and if we are successfull in getting a contract it would mean some development time for PostgreSQL code base itself. It doesn't matter where you live, but must be willing to travel occasionally if we get a contract. You would also be required to volunteer to help out prepare the RFP in places that apply to database backends. I'm not sure at this point what that will entail because I don't have the RFP yet. The actual work, of course will be paid. We will consider partner companies as well, and are putting together a list of requirements. Will post them here (or if someone suggests a different place) when they are ready. Richard Schilling www.rsmba.biz ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
