postgresql/src/backend/parser
Tom Lane 50fc694e43 Invent "trusted" extensions, and remove the pg_pltemplate catalog.
This patch creates a new extension property, "trusted".  An extension
that's marked that way in its control file can be installed by a
non-superuser who has the CREATE privilege on the current database,
even if the extension contains objects that normally would have to be
created by a superuser.  The objects within the extension will (by
default) be owned by the bootstrap superuser, but the extension itself
will be owned by the calling user.  This allows replicating the old
behavior around trusted procedural languages, without all the
special-case logic in CREATE LANGUAGE.  We have, however, chosen to
loosen the rules slightly: formerly, only a database owner could take
advantage of the special case that allowed installation of a trusted
language, but now anyone who has CREATE privilege can do so.

Having done that, we can delete the pg_pltemplate catalog, moving the
knowledge it contained into the extension script files for the various
PLs.  This ends up being no change at all for the in-core PLs, but it is
a large step forward for external PLs: they can now have the same ease
of installation as core PLs do.  The old "trusted PL" behavior was only
available to PLs that had entries in pg_pltemplate, but now any
extension can be marked trusted if appropriate.

This also removes one of the stumbling blocks for our Python 2 -> 3
migration, since the association of "plpythonu" with Python 2 is no
longer hard-wired into pg_pltemplate's initial contents.  Exactly where
we go from here on that front remains to be settled, but one problem
is fixed.

Patch by me, reviewed by Peter Eisentraut, Stephen Frost, and others.

Discussion: https://postgr.es/m/5889.1566415762@sss.pgh.pa.us
2020-01-29 18:42:43 -05:00
..
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:04 +02:00
Makefile Split all OBJS style lines in makefiles into one-line-per-entry style. 2019-11-05 14:41:07 -08:00
README Move keywords.c/kwlookup.c into src/common/. 2016-03-23 20:22:08 -04:00
analyze.c Reconsider the representation of join alias Vars. 2020-01-09 11:56:59 -05:00
check_keywords.pl Update copyrights for 2020 2020-01-01 12:21:45 -05:00
gram.y Invent "trusted" extensions, and remove the pg_pltemplate catalog. 2020-01-29 18:42:43 -05:00
parse_agg.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_clause.c Reconsider the representation of join alias Vars. 2020-01-09 11:56:59 -05:00
parse_coerce.c Make parser rely more heavily on the ParseNamespaceItem data structure. 2020-01-02 11:29:01 -05:00
parse_collate.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_cte.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_enr.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_expr.c Make parser rely more heavily on the ParseNamespaceItem data structure. 2020-01-02 11:29:01 -05:00
parse_func.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_node.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_oper.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_param.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_relation.c Reconsider the representation of join alias Vars. 2020-01-09 11:56:59 -05:00
parse_target.c Reconsider the representation of join alias Vars. 2020-01-09 11:56:59 -05:00
parse_type.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00
parse_utilcmd.c Restructure ALTER TABLE execution to fix assorted bugs. 2020-01-15 18:49:24 -05:00
parser.c Reduce size of backend scanner's tables. 2020-01-13 15:04:31 -05:00
scan.l Reduce size of backend scanner's tables. 2020-01-13 15:04:31 -05:00
scansup.c Update copyrights for 2020 2020-01-01 12:21:45 -05:00

README

src/backend/parser/README

Parser
======

This directory does more than tokenize and parse SQL queries.  It also
creates Query structures for the various complex queries that are passed
to the optimizer and then executor.

parser.c	things start here
scan.l		break query into tokens
scansup.c	handle escapes in input strings
gram.y		parse the tokens and produce a "raw" parse tree
analyze.c	top level of parse analysis for optimizable queries
parse_agg.c	handle aggregates, like SUM(col1),  AVG(col2), ...
parse_clause.c	handle clauses like WHERE, ORDER BY, GROUP BY, ...
parse_coerce.c	handle coercing expressions to different data types
parse_collate.c	assign collation information in completed expressions
parse_cte.c	handle Common Table Expressions (WITH clauses)
parse_expr.c	handle expressions like col, col + 3, x = 3 or x = 4
parse_func.c	handle functions, table.column and column identifiers
parse_node.c	create nodes for various structures
parse_oper.c	handle operators in expressions
parse_param.c	handle Params (for the cases used in the core backend)
parse_relation.c support routines for tables and column handling
parse_target.c	handle the result list of the query
parse_type.c	support routines for data type handling
parse_utilcmd.c	parse analysis for utility commands (done at execution time)

See also src/common/keywords.c, which contains the table of standard
keywords and the keyword lookup function.  We separated that out because
various frontend code wants to use it too.