Re: [HACKERS] LISTEN / NOTIFY enhancement request for Postgresql
Hello, Sev. You wrote: SZ Thank you all for considering my feature request. SZ Dimitri's suggestion is a very good one - I feel it will accomplish the SZ goal of allowing more granularity in the Listen. SZ We might also want to add a flag in postgresql.conf to disable this SZ enhancement so that we don't break existing code. I suppose it should be GUC variable (not only global entry) for per session settings. SZ On 11/15/2013 8:19 AM, Pavel Golub wrote: Hello, Dimitri. You wrote: DF Bruce Momjian br...@momjian.us writes: • is used to separate names in a path • * is used to match any name in a path • is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible Subscription Meaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.* Any stock price on NASDAQ PRICE.STOCK.*.IBMAny IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. This does seem useful and pretty easy to implement. Should we add a TODO? DF I think we should consider the ltree syntax in that case, as documented DF in the following link: DF http://www.postgresql.org/docs/9.3/interactive/ltree.html Great idea! Thanks for link. DF Regards, DF -- DF Dimitri Fontaine DF http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- With best wishes, Pavel mailto:pa...@gf.microolap.com -- 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] LISTEN / NOTIFY enhancement request for Postgresql
On Mon, Nov 18, 2013 at 09:15:39AM -0500, Sev Zaslavsky wrote: Thank you all for considering my feature request. Dimitri's suggestion is a very good one - I feel it will accomplish the goal of allowing more granularity in the Listen. We might also want to add a flag in postgresql.conf to disable this enhancement so that we don't break existing code. TODO added. -- Bruce Momjian br...@momjian.ushttp://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- 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] LISTEN / NOTIFY enhancement request for Postgresql
Thank you all for considering my feature request. Dimitri's suggestion is a very good one - I feel it will accomplish the goal of allowing more granularity in the Listen. We might also want to add a flag in postgresql.conf to disable this enhancement so that we don't break existing code. On 11/15/2013 8:19 AM, Pavel Golub wrote: Hello, Dimitri. You wrote: DF Bruce Momjian br...@momjian.us writes: • is used to separate names in a path • * is used to match any name in a path • is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible Subscription Meaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.* Any stock price on NASDAQ PRICE.STOCK.*.IBMAny IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. This does seem useful and pretty easy to implement. Should we add a TODO? DF I think we should consider the ltree syntax in that case, as documented DF in the following link: DF http://www.postgresql.org/docs/9.3/interactive/ltree.html Great idea! Thanks for link. DF Regards, DF -- DF Dimitri Fontaine DF http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- 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] LISTEN / NOTIFY enhancement request for Postgresql
Hello, Dimitri. You wrote: DF Bruce Momjian br...@momjian.us writes: • is used to separate names in a path • * is used to match any name in a path • is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible Subscription Meaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.* Any stock price on NASDAQ PRICE.STOCK.*.IBMAny IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. This does seem useful and pretty easy to implement. Should we add a TODO? DF I think we should consider the ltree syntax in that case, as documented DF in the following link: DF http://www.postgresql.org/docs/9.3/interactive/ltree.html Great idea! Thanks for link. DF Regards, DF -- DF Dimitri Fontaine DF http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- With best wishes, Pavel mailto:pa...@gf.microolap.com -- 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] LISTEN / NOTIFY enhancement request for Postgresql
On Thu, Oct 24, 2013 at 11:41:57AM -0400, Sev Zaslavsky wrote: Here is an example implementation: http://activemq.apache.org/nms/ activemq-wildcards.html • is used to separate names in a path • * is used to match any name in a path • is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible Subscription Meaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.* Any stock price on NASDAQ PRICE.STOCK.*.IBMAny IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. This does seem useful and pretty easy to implement. Should we add a TODO? -- Bruce Momjian br...@momjian.ushttp://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- 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] LISTEN / NOTIFY enhancement request for Postgresql
Bruce Momjian br...@momjian.us writes: • is used to separate names in a path • * is used to match any name in a path • is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible Subscription Meaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.* Any stock price on NASDAQ PRICE.STOCK.*.IBMAny IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. This does seem useful and pretty easy to implement. Should we add a TODO? I think we should consider the ltree syntax in that case, as documented in the following link: http://www.postgresql.org/docs/9.3/interactive/ltree.html Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] LISTEN / NOTIFY enhancement request for Postgresql
Hi pgsql-hackers, The LISTEN / NOTIFY feature (along with the pg_notify() function) is a unique feature that differentiates Postgresql from nearly all other relational database systems. With the exception of SQL Server, I know of no other RDBMSs that allow a client to be asynchronously notified by the database server. This feature embodies the modern push approach and allows delivering timely data to the user as it changes, instead of the more traditional pull approach which requires the user to request the data at specific intervals. Vendors are rolling out push technologies to meet market demand. Microsoft recently introduced SignalR - which is a framework for pushing content to ASP.NET Web pages. Similarly Complex Event Processing systems push information to users' dashboards in real-time. In contrast with RDBMS's where asynchronous notification is a special feature, message broker software implementations live and breathe asynchronous notification.So I feel that the LISTEN / NOTIFY feature is trying to deliver some of the asynchronous notification features of a message broker but it lacks some of the flexibility. One particular shortcoming of LISTEN / NOTIFY is the fact that the channel specified on the LISTEN must _exactly _match the channel specified on the NOTIFY. Here is an example of the problem: I have two listeners: 1. Interested in all stock quote updates 2. Interested in stock quote updates for IBM only There is a table that contains stock prices with a trigger proc that issues a NOTIFY using pg_notify() upon update. There isn't a single channel that I can use that will deliver the message to both listeners. To get around the problem I could publish a message on channel PRICE and another message on channel PRICE.IBM but sending two notifications is far from optimal. Message brokers have implemented a neat way to get around this issue. It is accomplished by allowing wildcards in message topic subscriptions. Here is an example implementation:http://activemq.apache.org/nms/activemq-wildcards.html * is used to separate names in a path * * is used to match any name in a path * is used to recursively match any destination starting from this name For example using the example above, these subscriptions are possible SubscriptionMeaning PRICE. Any price for any product on any exchange PRICE.STOCK.Any price for a stock on any exchange PRICE.STOCK.NASDAQ.*Any stock price on NASDAQ PRICE.STOCK.*.IBM Any IBM stock price on any exchange My request is to implement the same or similar feature in Postgresql. Thank you. -Sev
