diff options
| -rw-r--r-- | doc/src/sgml/plperl.sgml | 8 | ||||
| -rw-r--r-- | doc/src/sgml/plpgsql.sgml | 41 | ||||
| -rw-r--r-- | doc/src/sgml/pltcl.sgml | 43 |
3 files changed, 59 insertions, 33 deletions
diff --git a/doc/src/sgml/plperl.sgml b/doc/src/sgml/plperl.sgml index 94a375587fc..12ac0157c3e 100644 --- a/doc/src/sgml/plperl.sgml +++ b/doc/src/sgml/plperl.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.54 2006/05/29 13:51:23 adunstan Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.55 2006/05/30 11:40:21 momjian Exp $ --> <chapter id="plperl"> <title>PL/Perl - Perl Procedural Language</title> @@ -17,6 +17,12 @@ <ulink url="http://www.perl.com">Perl programming language</ulink>. </para> + <para> The usual advantage to using PL/Perl is that this allows use, + within stored functions, of the manyfold <quote>string + munging</quote> operators and functions available for Perl. Parsing + complex strings may be be easier using Perl than it is with the + string functions and control structures provided in PL/pgsql.</para> + <para> To install PL/Perl in a particular database, use <literal>createlang plperl <replaceable>dbname</></literal>. diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 4f302a858e7..2fc998ee909 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.89 2006/05/28 03:03:17 adunstan Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.90 2006/05/30 11:40:21 momjian Exp $ --> <chapter id="plpgsql"> <title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title> @@ -155,21 +155,36 @@ $$ LANGUAGE plpgsql; <para> That means that your client application must send each query to - the database server, wait for it to be processed, receive the - results, do some computation, then send other queries to the - server. All this incurs interprocess communication and may also - incur network overhead if your client is on a different machine - than the database server. + the database server, wait for it to be processed, receive and + process the results, do some computation, then send further + queries to the server. All this incurs interprocess + communication and will also incur network overhead if your client + is on a different machine than the database server. </para> <para> - With <application>PL/pgSQL</application> you can group a block of computation and a - series of queries <emphasis>inside</emphasis> the - database server, thus having the power of a procedural - language and the ease of use of SQL, but saving lots of - time because you don't have the whole client/server - communication overhead. This can make for a - considerable performance increase. + With <application>PL/pgSQL</application> you can group a block of + computation and a series of queries <emphasis>inside</emphasis> + the database server, thus having the power of a procedural + language and the ease of use of SQL, but with considerable + savings because you don't have the whole client/server + communication overhead. + </para> + <itemizedlist> + + <listitem><para> Elimination of additional round trips between + client and server </para></listitem> + + <listitem><para> Intermediate results that the client does not + need do not need to be marshalled or transferred between server + and client </para></listitem> + + <listitem><para> There is no need for additional rounds of query + parsing </para></listitem> + + </itemizedlist> + <para> This can allow for a considerable performance increase as + compared to an application that does not use stored functions. </para> <para> diff --git a/doc/src/sgml/pltcl.sgml b/doc/src/sgml/pltcl.sgml index 3ffaf81fe5e..d4bdabeeaed 100644 --- a/doc/src/sgml/pltcl.sgml +++ b/doc/src/sgml/pltcl.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.40 2006/05/27 20:24:16 adunstan Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/pltcl.sgml,v 2.41 2006/05/30 11:40:21 momjian Exp $ --> <chapter id="pltcl"> <title>PL/Tcl - Tcl Procedural Language</title> @@ -25,22 +25,27 @@ <title>Overview</title> <para> - PL/Tcl offers most of the capabilities a function - writer has in the C language, except for some restrictions. + PL/Tcl offers most of the capabilities a function writer has in + the C language, with a few restrictions, and with the addition of + the powerful string processing libraries that are available for + Tcl. </para> <para> - The good restriction is that everything is executed in a safe - Tcl interpreter. In addition to the limited command set of safe Tcl, only - a few commands are available to access the database via SPI and to raise - messages via <function>elog()</>. There is no way to access internals of the - database server or to gain OS-level access under the permissions of the - <productname>PostgreSQL</productname> server process, as a C function can do. - Thus, any unprivileged database user may be - permitted to use this language. + One compelling <emphasis>good</emphasis> restriction is that + everything is executed from within the safety of the context of a + Tcl interpreter. In addition to the limited command set of safe + Tcl, only a few commands are available to access the database via + SPI and to raise messages via <function>elog()</>. PL/Tcl + provides no way to access internals of the database server or to + gain OS-level access under the permissions of the + <productname>PostgreSQL</productname> server process, as a C + function can do. Thus, unprivileged database users may be trusted + to use this language; it does not give them unlimited authority. </para> <para> - The other, implementation restriction is that Tcl functions cannot - be used to create input/output functions for new data types. + The other notable implementation restriction is that Tcl functions + may not be used to create input/output functions for new data + types. </para> <para> Sometimes it is desirable to write Tcl functions that are not restricted @@ -55,12 +60,12 @@ a user logged in as the database administrator. </para> <para> - The shared object for the <application>PL/Tcl</> and <application>PL/TclU</> call handlers is - automatically built and installed in the - <productname>PostgreSQL</productname> - library directory if Tcl support is specified - in the configuration step of the installation procedure. To install - <application>PL/Tcl</> and/or <application>PL/TclU</> in a particular database, use the + The shared object code for the <application>PL/Tcl</> and + <application>PL/TclU</> call handlers is automatically built and + installed in the <productname>PostgreSQL</productname> library + directory if Tcl support is specified in the configuration step of + the installation procedure. To install <application>PL/Tcl</> + and/or <application>PL/TclU</> in a particular database, use the <command>createlang</command> program, for example <literal>createlang pltcl <replaceable>dbname</></literal> or <literal>createlang pltclu <replaceable>dbname</></literal>. |