postgresql/src/include/rewrite/rewriteDefine.h

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/*-------------------------------------------------------------------------
*
* rewriteDefine.h
*
*
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
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* src/include/rewrite/rewriteDefine.h
*
*-------------------------------------------------------------------------
*/
#ifndef REWRITEDEFINE_H
#define REWRITEDEFINE_H
#include "catalog/objectaddress.h"
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#include "nodes/parsenodes.h"
#include "utils/relcache.h"
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Changes pg_trigger and extend pg_rewrite in order to allow triggers and rules to be defined with different, per session controllable, behaviors for replication purposes. This will allow replication systems like Slony-I and, as has been stated on pgsql-hackers, other products to control the firing mechanism of triggers and rewrite rules without modifying the system catalog directly. The firing mechanisms are controlled by a new superuser-only GUC variable, session_replication_role, together with a change to pg_trigger.tgenabled and a new column pg_rewrite.ev_enabled. Both columns are a single char data type now (tgenabled was a bool before). The possible values in these attributes are: 'O' - Trigger/Rule fires when session_replication_role is "origin" (default) or "local". This is the default behavior. 'D' - Trigger/Rule is disabled and fires never 'A' - Trigger/Rule fires always regardless of the setting of session_replication_role 'R' - Trigger/Rule fires when session_replication_role is "replica" The GUC variable can only be changed as long as the system does not have any cached query plans. This will prevent changing the session role and accidentally executing stored procedures or functions that have plans cached that expand to the wrong query set due to differences in the rule firing semantics. The SQL syntax for changing a triggers/rules firing semantics is ALTER TABLE <tabname> <when> TRIGGER|RULE <name>; <when> ::= ENABLE | ENABLE ALWAYS | ENABLE REPLICA | DISABLE psql's \d command as well as pg_dump are extended in a backward compatible fashion. Jan
2007-03-20 00:38:32 +01:00
#define RULE_FIRES_ON_ORIGIN 'O'
#define RULE_FIRES_ALWAYS 'A'
#define RULE_FIRES_ON_REPLICA 'R'
#define RULE_DISABLED 'D'
extern ObjectAddress DefineRule(RuleStmt *stmt, const char *queryString);
extern ObjectAddress DefineQueryRewrite(const char *rulename,
Fix a couple of misbehaviors rooted in the fact that the default creation namespace isn't necessarily first in the search path (there could be implicit schemas ahead of it). Examples are test=# set search_path TO s1; test=# create view pg_timezone_names as select * from pg_timezone_names(); ERROR: "pg_timezone_names" is already a view test=# create table pg_class (f1 int primary key); ERROR: permission denied: "pg_class" is a system catalog You'd expect these commands to create the requested objects in s1, since names beginning with pg_ aren't supposed to be reserved anymore. What is happening is that we create the requested base table and then execute additional commands (here, CREATE RULE or CREATE INDEX), and that code is passed the same RangeVar that was in the original command. Since that RangeVar has schemaname = NULL, the secondary commands think they should do a path search, and that means they find system catalogs that are implicitly in front of s1 in the search path. This is perilously close to being a security hole: if the secondary command failed to apply a permission check then it'd be possible for unprivileged users to make schema modifications to system catalogs. But as far as I can find, there is no code path in which a check doesn't occur. Which makes it just a weird corner-case bug for people who are silly enough to want to name their tables the same as a system catalog. The relevant code has changed quite a bit since 8.2, which means this patch wouldn't work as-is in the back branches. Since it's a corner case no one has reported from the field, I'm not going to bother trying to back-patch.
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Oid event_relid,
Node *event_qual,
CmdType event_type,
bool is_instead,
bool replace,
List *action);
extern ObjectAddress RenameRewriteRule(RangeVar *relation, const char *oldName,
const char *newName);
extern void setRuleCheckAsUser(Node *node, Oid userid);
Changes pg_trigger and extend pg_rewrite in order to allow triggers and rules to be defined with different, per session controllable, behaviors for replication purposes. This will allow replication systems like Slony-I and, as has been stated on pgsql-hackers, other products to control the firing mechanism of triggers and rewrite rules without modifying the system catalog directly. The firing mechanisms are controlled by a new superuser-only GUC variable, session_replication_role, together with a change to pg_trigger.tgenabled and a new column pg_rewrite.ev_enabled. Both columns are a single char data type now (tgenabled was a bool before). The possible values in these attributes are: 'O' - Trigger/Rule fires when session_replication_role is "origin" (default) or "local". This is the default behavior. 'D' - Trigger/Rule is disabled and fires never 'A' - Trigger/Rule fires always regardless of the setting of session_replication_role 'R' - Trigger/Rule fires when session_replication_role is "replica" The GUC variable can only be changed as long as the system does not have any cached query plans. This will prevent changing the session role and accidentally executing stored procedures or functions that have plans cached that expand to the wrong query set due to differences in the rule firing semantics. The SQL syntax for changing a triggers/rules firing semantics is ALTER TABLE <tabname> <when> TRIGGER|RULE <name>; <when> ::= ENABLE | ENABLE ALWAYS | ENABLE REPLICA | DISABLE psql's \d command as well as pg_dump are extended in a backward compatible fashion. Jan
2007-03-20 00:38:32 +01:00
extern void EnableDisableRule(Relation rel, const char *rulename,
char fires_when);
#endif /* REWRITEDEFINE_H */