Обсуждение: Re: [GENERAL] Postgres 7.4 : ECPG not Thread-safe
Thierry Missimilly wrote: > Thank you Bruce. > You've had a good idea to send me your little program. > I well understand the concept of "Named connection for each thread", but could you tell me where i can find a doc wherethe use of "EXEC SQL AT > ..." is describe ? > > May i suggest to put some lines about that in the "Programmer's Guide" ?4 ECPG - Embedded SQL in C, as I have based mydevelopment on this doc > and it could be useful for other user to know how to code in Multi-thread context. Yes, our docs are petty sparse on ecpg. It is basically the same as SQL-standard embedded C, so any docs on that would be the same for ecpg. Interfaces list, where is there detailed ecpg documentaiton, like documentation on the AT clause? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Thu, 13 Nov 2003 03:16 pm, Bruce Momjian wrote: > Interfaces list, where is there detailed ecpg documentaiton, like > documentation on the AT clause? I'm willing to have a go at updating the doco. Can someone point me to a guide to getting started with the markup we use? Regards, Philip.
Philip Yarra wrote: > On Thu, 13 Nov 2003 03:16 pm, Bruce Momjian wrote: > > Interfaces list, where is there detailed ecpg documentaiton, like > > documentation on the AT clause? > > I'm willing to have a go at updating the doco. Can someone point me to a guide > to getting started with the markup we use? Great, but be warned --- the work is huge. Basically, ecpg is a full ANSI SQL-standard C interface to PostgreSQL. It is the only ANSI standard application interface we support, I think. Let me also add that it is totally cool! It doesn't look all that friendly, but once you start coding in it, and pass variables in and out of queries, it takes on amazing power and has amazing clarity. If I was coding an app in C, it would be the interface I would use. libpq requires just too much house-cleaning for me. Anyway, I think you can grab any ANSI SQL enbedded document and get ideas. You can look at vendors docs because those are going to be very similar, and you can look at the ANSI standard for ideas. Of course, check out what you see against our existing grammer to be sure we support it, but once you are done, I think you could create a document that really shows the power of ecpg --- right now, our docs don't do it justice. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Philip Yarra wrote: > On Thu, 13 Nov 2003 03:16 pm, Bruce Momjian wrote: > > Interfaces list, where is there detailed ecpg documentaiton, like > > documentation on the AT clause? > > I'm willing to have a go at updating the doco. Can someone point me to a guide > to getting started with the markup we use? You can just write it and we can add markup, or you can add SGML tags --- just use tags from similar sections as examples of how to do it --- at least that's how I do it, then Peter cleans it up for me. :-) -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Thu, 13 Nov 2003 03:47 pm, Bruce Momjian wrote: > Philip Yarra wrote: > > I'm willing to have a go at updating the doco. Can someone point me to a > > guide to getting started with the markup we use? > > Great, but be warned --- the work is huge. Yikes! I just figured updating the manual section would be a good start. I'll deal with *huge* later. > Let me also add > that it is totally cool! It doesn't look all that friendly, but once > you start coding in it, and pass variables in and out of queries, it > takes on amazing power and has amazing clarity. Personally I don't really like embedded SQL, and would prefer libpq, except for one beautiful feature: it's quite portable (Informix->Sybase->PostgreSQL with minimal re-coding). > Anyway, I think you can grab any ANSI SQL enbedded document and get > ideas. You can look at vendors docs because those are going to be very > similar, and you can look at the ANSI standard for ideas. I have some of the vendors' ones to look at for ideas. Is the ANSI doc (freely) available? > that really shows the power of ecpg --- right now, our docs don't do it > justice. Agreed. I'll see what I can do. I figure just adding "always use 'AT connection_name' in a threaded application or suffer the consequences" would be a good start. Regards, Philip.
Philip Yarra wrote: > On Thu, 13 Nov 2003 03:47 pm, Bruce Momjian wrote: > > Philip Yarra wrote: > > > I'm willing to have a go at updating the doco. Can someone point me to a > > > guide to getting started with the markup we use? > > > > Great, but be warned --- the work is huge. > > Yikes! I just figured updating the manual section would be a good start. I'll > deal with *huge* later. > > > Let me also add > > that it is totally cool! It doesn't look all that friendly, but once > > you start coding in it, and pass variables in and out of queries, it > > takes on amazing power and has amazing clarity. > > Personally I don't really like embedded SQL, and would prefer libpq, except > for one beautiful feature: it's quite portable (Informix->Sybase->PostgreSQL > with minimal re-coding). > > > Anyway, I think you can grab any ANSI SQL enbedded document and get > > ideas. You can look at vendors docs because those are going to be very > > similar, and you can look at the ANSI standard for ideas. > > I have some of the vendors' ones to look at for ideas. > > Is the ANSI doc (freely) available? Just grab a draft as mentioned in our developers FAQ. > > that really shows the power of ecpg --- right now, our docs don't do it > > justice. > > Agreed. I'll see what I can do. I figure just adding "always use 'AT > connection_name' in a threaded application or suffer the consequences" would > be a good start. I guess, but there still a lot missing. I wonder if we should just find a good document on the web and point people there --- why reinvent the wheel. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Thu, Nov 13, 2003 at 03:35:31PM +1100, Philip Yarra wrote: > On Thu, 13 Nov 2003 03:16 pm, Bruce Momjian wrote: > > Interfaces list, where is there detailed ecpg documentaiton, like > > documentation on the AT clause? > > I'm willing to have a go at updating the doco. Can someone point me to a guide > to getting started with the markup we use? It's SGML. The file in question is pgsql/doc/src/sgml/ecpg.sgml. Michael -- Michael Meskes Email: Michael at Fam-Meskes dot De ICQ: 179140304, AIM/Yahoo: michaelmeskes, Jabber: meskes@jabber.org Go SF 49ers! Go Rhein Fire! Use Debian GNU/Linux! Use PostgreSQL!
On Wed, Nov 12, 2003 at 11:16:10PM -0500, Bruce Momjian wrote: > Yes, our docs are petty sparse on ecpg. It is basically the same as > SQL-standard embedded C, so any docs on that would be the same for ecpg. > > Interfaces list, where is there detailed ecpg documentaiton, like > documentation on the AT clause? Our docs say: ... <para> The first option is to explicitly choose a connection for each SQL statement, for example <programlisting> EXEC SQL AT <replaceable>connection-name</replaceable> SELECT ...; </programlisting> This option is particularly suitable if the application needs to use several connections in mixed order.</para> So it's not as if it wasn't noted at all. Okay, this is in 7.4, 7.3 docs are not nearly as good as Peter spend some time enhancing the docs for 7.4. Michael -- Michael Meskes Email: Michael at Fam-Meskes dot De ICQ: 179140304, AIM/Yahoo: michaelmeskes, Jabber: meskes@jabber.org Go SF 49ers! Go Rhein Fire! Use Debian GNU/Linux! Use PostgreSQL!