PLV8 is a programming language that lets users write stored procedures and triggers in JavaScript and store them in their Postgres database. This allows application programmers to write a lot of their server-side programming in the same language they use to build their web client applications. Fewer languages to learn usually means fewer mistakes and faster time to completion. The extensive language support is one of many reasons why Postgres’ use across the world is increasing lately. The recent addition of document data support with JSON and JSONB data types in PostgreSQL, and in Postgres Plus Advanced Server from EnterpriseDB, is the main reason for the increasing interest in the PL/V8 language extension.
Below are the steps you need to compile PLV8 with Postgres Plus Advanced Server 9.3/9.4.
To get started, here are the prerequisites:
1. A supported version of PostgreSQL or Postgres Plus Advanced Server, such as versions 9.1 and higher.
2. V8 version 3.14.5
3. g++ version 4.5.1
If you want to know more about V8, you can visit the following wiki page:
http://en.wikipedia.org/wiki/V8_(JavaScript_engine)
It’s important to note that when compiling PLV8 with Postgres Plus Advanced Server 9.3 or the upcoming 9.4, you will get the following two types of error messages:
The first error:
[root@localhost plv8js]# make
sed -e 's/^#undef PLV8_VERSION/#define PLV8_VERSION "1.5.0-dev1"/'plv8_config.h.in > plv8_config.h g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8.o plv8.cc
plv8.cc: In function ‘void _PG_init()’:
plv8.cc:226: error: invalid conversion from ‘void (*)(XactEvent, void*)’ to ‘void (*)(XactEvent, void*, bool)’
plv8.cc:226: error: initializing argument 1 of ‘void RegisterXactCallback(void (*)(XactEvent, void*, bool), void*)’
make: *** [plv8.o] Error 1
The above error message is a result of a different signature of typedef void (*XactCallback) in the Advanced Server transaction system.
To fix the above issue, the user can replace the following in plv8.cc:
static void plv8_xact_cb(XactEvent event, void *arg);
With
static void plv8_xact_cb(XactEvent event, void *arg, bool spl_context);
The second error:
After making the above changes, you may get the following error after trying to compile the source code using the “make” command:
[root@localhost plv8js]# make
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8.o plv8.cc
plv8.cc:137: warning: ‘void plv8_xact_cb(XactEvent, void*, bool)’ used but never defined
plv8.cc:232: warning: ‘void plv8_xact_cb(XactEvent, void*)’ defined but not used
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8_type.o plv8_type.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8_func.o plv8_func.cc
In file included from plv8_param.h:11,
from plv8_func.cc:9:
/usr/ppas-9.4/include/server/nodes/params.h:77: error: expected ‘,’ or ‘...’ before ‘typeid’
make: *** [plv8_func.o] Error 1
The above is mainly due to the use of typeid in params.h; typeid is the reserved keyword of C++ compiler.
To fix this issue, make the following changes in plv8.h
extern "C" {
#include "postgres.h"
#include "access/htup.h"
#include "fmgr.h"
#include "mb/pg_wchar.h"
#include "utils/tuplestore.h"
#include "windowapi.h"
}
with
#define typeid __typeid
extern "C" {
#include "postgres.h"
#include "access/htup.h"
#include "fmgr.h"
#include "mb/pg_wchar.h"
#include "utils/tuplestore.h"
#include "windowapi.h"
}
#undef typeid
In plv8_param.h, change the following:
extern "C" {
#include "postgres.h"
/*
* Variable SPI parameter is since 9.0. Avoid include files in prior versions,
* as they contain C++ keywords.
*/
#include "nodes/params.h"
#if PG_VERSION_NUM >= 90000
#include "parser/parse_node.h"
#endif // PG_VERSION_NUM >= 90000
} // extern "C"
With
#define typeid __typeid
extern "C" {
#include "postgres.h"
/*
* Variable SPI parameter is since 9.0. Avoid including files in prior versions,
* as they contain C++ keywords.
*/
#include "nodes/params.h"
#if PG_VERSION_NUM >= 90000
#include "parser/parse_node.h"
#endif // PG_VERSION_NUM >= 90000
} // extern "C"
#undef typeid
In plv8_param.cc, replace following:
extern "C" {
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
} // extern "C"
with
#define typeid __typeid
extern "C" {
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
} // extern "C"
#undef typeid
After making the above changes, you will be able to compile PLV8 with Advanced Server as shown below:
[root@localhost plv8js]# make
sed -e 's/^#undef PLV8_VERSION/#define PLV8_VERSION "1.5.0-dev1"/' plv8_config.h.in > plv8_config.h
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8.o plv8.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8_type.o plv8_type.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8_func.o plv8_func.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o plv8_param.o plv8_param.cc
echo "extern const unsigned char coffee_script_binary_data[] = {" >coffee-script.cc
(od -txC -v coffee-script.js | \
sed -e "s/^[0-9]*//" -e s"/ \([0-9a-f][0-9a-f]\)/0x\1,/g" -e"\$d" ) >>coffee-script.cc
echo "0x00};" >>coffee-script.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o coffee-script.o coffee-script.cc
echo "extern const unsigned char livescript_binary_data[] = {" >livescript.cc
(od -txC -v livescript.js | \
sed -e "s/^[0-9]*//" -e s"/ \([0-9a-f][0-9a-f]\)/0x\1,/g" -e"\$d" ) >>livescript.cc
echo "0x00};" >>livescript.cc
g++ -Wall -O2 -DV8_USE_UNSAFE_HANDLES -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -fPIC -c -o livescript.o livescript.cc
g++ -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -I/usr/include/et -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fpic -shared -o plv8.so plv8.o plv8_type.o plv8_func.o plv8_param.o coffee-script.o livescript.o -L/usr/ppas-9.4/lib -L/usr/lib64 -Wl,--as-needed -Wl,-rpath,'/usr/ppas-9.4/lib',--enable-new-dtags -lv8
sed -e 's/@PLV8_VERSION@/1.5.0-dev1/g' plv8.control.common | g++ -E -P -DLANG_plv8 - > plv8.control
sed -e 's/@LANG_NAME@/plv8/g' plv8.sql.common | g++ -E -P -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -DLANG_plv8 - > plv8--1.5.0-dev1.sql
sed -e 's/@PLV8_VERSION@/1.5.0-dev1/g' plv8.control.common | g++ -E -P -DLANG_plcoffee - > plcoffee.control
sed -e 's/@LANG_NAME@/plcoffee/g' plv8.sql.common | g++ -E -P -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -DLANG_plcoffee - > plcoffee--1.5.0-dev1.sql
sed -e 's/@PLV8_VERSION@/1.5.0-dev1/g' plv8.control.common | g++ -E -P -DLANG_plls - > plls.control
sed -e 's/@LANG_NAME@/plls/g' plv8.sql.common | g++ -E -P -I. -I./ -I/usr/ppas-9.4/include/server -I/usr/ppas-9.4/include/internal -I/usr/include/et -D_GNU_SOURCE -I/usr/include/libxml2 -I/usr/include -DLANG_plls - > plls--1.5.0-dev1.sql
/bin/mkdir -p '/usr/ppas-9.4/lib'
/bin/mkdir -p '/usr/ppas-9.4/share/extension'
/bin/mkdir -p '/usr/ppas-9.4/share/extension'
/usr/bin/install -c -m 755 plv8.so '/usr/ppas-9.4/lib/plv8.so'
/usr/bin/install -c -m 644 plv8.control '/usr/ppas-9.4/share/extension/'
/usr/bin/install -c -m 644 plv8.control plv8--1.5.0-dev1.sql plcoffee.control plcoffee--1.5.0-dev1.sql plls.control plls--1.5.0-dev1.sql '/usr/ppas-9.4/share/extension/'
After compiling PLV8, you now can install the PLV8 language in Advanced Server using the following command:
beta=# CREATE EXTENSION PLV8;
CREATE EXTENSION
beta=#
To test your installed PLV8, here is some sample code:
beta=# DO $$ PLV8.elog(NOTICE, 'this', 'is', 'inline', 'code') $$ LANGUAGE PLV8;
NOTICE: this is inline code
DO
beta=# CREATE TYPE rec AS (i integer, t text);
CREATE TYPE
beta=# CREATE FUNCTION set_of_records() RETURNS SETOF rec AS
beta-# $$
beta$# // PLV8.return_next() stores records in an internal tuplestore,
beta$# // and return all of them at the end of function.
beta$# PLV8.return_next( { "i": 1, "t": "a" } );
beta$# PLV8.return_next( { "i": 2, "t": "b" } );
beta$#
beta$# // You can also return records with an array of JSON.
beta$# return [ { "i": 3, "t": "c" }, { "i": 4, "t": "d" } ];
beta$# $$
beta-# LANGUAGE PLV8;
CREATE FUNCTION
beta=# SELECT * FROM set_of_records();
i | t
---+---
1 | a
2 | b
3 | c
4 | d
(4 rows)
In case you need a patched version of PLV8, use the following git repository:
https://github.com/vibhorkum/PLV8_FOR_PPAS.git PLV8_ppas
To use this, execute the following command:
git clone https://github.com/vibhorkum/PLV8_FOR_PPAS.git PLV8_ppas
cd PLV8_ppas
make
make install
To test the compiled PLV8, you can use the following command:
[root@localhost plv8js]# make installcheck
/usr/ppas-9.4/lib/pgxs/src/makefiles/../../src/test/regress/pg_regress --inputdir=./ --psqldir='/usr/ppas-9.4/bin' --dbname=contrib_regression init-extension plv8 inline json startup_pre startup varparam json_conv window dialect
(using postmaster on Unix socket, port 5444)
============== dropping database "contrib_regression" ==============
DROP DATABASE
============== creating database "contrib_regression" ==============
CREATE DATABASE
ALTER DATABASE
============== running regression test queries ==============
test init-extension ... ok
test plv8 ... ok
test inline ... ok
test json ... ok
test startup_pre ... ok
test startup ... ok
test varparam ... ok
test json_conv ... ok
test window ... ok
test dialect ... ok
======================
All 10 tests passed.
======================