SYSTEM CATALOGS(INTRO)

Section 7 - System Catalogs

DESCRIPTION
In this section we list each of the attributes of the system catalogs and define their meanings.

CLASS/TYPE SYSTEM CATALOGS
These catalogs form the core of the extensibility system:
    name    shared/local    description
    pg_aggregate    local    aggregate functions
    pg_am    local    access methods
    pg_amop    local    operators usable with specific access methods
    pg_amproc    local    procedures used with specific access methods
    pg_attribute    local    class attributes
    pg_class    local    classes
    pg_index    local    secondary indices
    pg_inherits    local    class inheritance hierarchy
    pg_language    local    procedure implementation languages
    pg_opclass    local    operator classes
    pg_operator    local    query language operators
    pg_proc    local    procedures (functions)
    pg_type    local    data types

ENTITIES
These catalogs deal with identification of entities known throughout the site:
    name    shared/local    description
    pg_database    shared    current databases
    pg_group    shared    user groups
    pg_shadow    shared    valid users

RULE SYSTEM CATALOGS
    name    shared/local    description
    pg_listener    local    processes waiting on alerters
    pg_prs2plans    local    instance system procedures
    pg_prs2rule    local    instance system rules
    pg_prs2stub    local    instance system ``stubs''
    pg_rewrite    local    rewrite system information

LARGE OBJECT CATALOGS

These catalogs are specific to the Inversion file system and large objects in general:
    name    shared/local    description
    pg_lobj    local    description of a large object
    pg_naming    local    Inversion name space mapping
    pg_platter    local    jukebox platter inventory
    pg_plmap    local    jukebox platter extent map

INTERNAL CATALOGS

These catalogs are internal classes that are not stored as normal heaps and cannot be accessed through normal means (attempting to do so causes an error).
    name    shared/local    description
    pg_log    shared    transaction commit/rollback log
    pg_magic    shared    magic constant
    pg_time    shared    commit/rollback times
    pg_variable    shared    special variable values

There are several other classes defined with “pg_” names. Aside from those that end in “ind” (secondary indices), these are all obsolete or otherwise deprecated.

CLASS/TYPE SYSTEM CATALOGS

The following catalogs relate to the class/type system.
/*
 * aggregates
 *
 * see DEFINE AGGREGATE for an explanation of transition functions
 */
pg_aggregate
    NameData      aggname	/* aggregate name (e.g., "count") */
    oid         aggowner	/* usesysid of creator */
    regproc     aggtransfn1	/* first transition function */
    regproc     aggtransfn2	/* second transition function */
    regproc     aggfinalfn	/* final function */
    oid         aggbasetype	/* type of data on which aggregate
				   operates */
    oid         aggtranstype1	/* type returned by aggtransfn1 */
    oid         aggtranstype2	/* type returned by aggtransfn2 */
    oid         aggfinaltype	/* type returned by aggfinalfn */
    text        agginitval1	/* external format of initial
				   (starting) value of aggtransfn1 */
    text        agginitval2	/* external format of initial
				   (starting) value of aggtransfn2 */
pg_am
    NameData      amname		/* access method name */
    oid         amowner	/* usesysid of creator */
    char        amkind		/* - deprecated */
				/* originally:
				   h=hashed
				   o=ordered
				   s=special */
    int2        amstrategies	/* total NUMBER of strategies by which
				   we can traverse/search this AM */
    int2        amsupport	/* total NUMBER of support functions
				   that this AM uses */
    regproc     amgettuple	/* "next valid tuple" function */
    regproc     aminsert	/* "insert this tuple" function */
    regproc     amdelete	/* "delete this tuple" function */
    regproc     amgetattr	/* - deprecated */
    regproc     amsetlock	/* - deprecated */
    regproc     amsettid	/* - deprecated */
    regproc     amfreetuple	/* - deprecated */
    regproc     ambeginscan	/* "start new scan" function */
    regproc     amrescan	/* "restart this scan" function */
    regproc     amendscan	/* "end this scan" function */
    regproc     ammarkpos	/* "mark current scan position"
				   function */
    regproc     amrestrpos	/* "restore marked scan position"
				   function */
    regproc     amopen		/* - deprecated */
    regproc     amclose	/* - deprecated */
    regproc     ambuild	/* "build new index" function */
    regproc     amcreate 	/* - deprecated */
    regproc     amdestroy	/* - deprecated */
pg_amop
    oid         amopid		/* access method with which this
				   operator be used */
    oid         amopclaid	/* operator class with which this
				   operator can be used */
    oid         amopopr	/* the operator */
    int2        amopstrategy	/* traversal/search strategy number
				   to which this operator applies */
    regproc     amopselect	/* function to calculate the operator
				   selectivity */
    regproc     amopnpages	/* function to calculate the number of
				   pages that will be examined */
pg_amproc
    oid         amid		/* access method with which this
				   procedure is associated */
    oid         amopclaid	/* operator class with which this
				   operator can be used */
    oid         amproc		/* the procedure */
    int2        amprocnum	/* support function number to which
				   this operator applies */
pg_class
     NameData     relname	/* class name */
     oid        relowner	/* usesysid of owner */
     oid        relam	/* access method */
     int4       relpages	/* # of 8KB pages */
     int4       reltuples	/* # of instances */
     abstime    relexpires	/* time after which instances are
				   deleted from non-archival storage */
     reltime    relpreserved	/* timespan after which instances are
				   deleted from non-archival storage */
     bool       relhasindex	/* does the class have a secondary
				   index? */
     bool       relisshared	/* is the class shared or local? */
     char       relkind		/* type of relation:
				   i=index
				   r=relation (heap)
				   s=special
				   u=uncatalogued (temporary) */
     char       relarch	/* archive mode:
			   h=heavy
			   l=light
			   n=none */
     int2       relnatts	/* current # of non-system
				   attributes */
     int2       relsmgr	/* storage manager:
			   0=magnetic disk
			   1=sony WORM jukebox
			   2=main memory */
     int28      relkey	/* - unused */
     oid8       relkeyop	/* - unused */
     aclitem    relacl[1]	/* access control lists */
pg_attribute
    oid         attrelid	/* class containing this attribute */
    NameData      attname	/* attribute name */
    oid         atttypid	/* attribute type */
    oid         attdefrel	/* - deprecated */
    int4        attnvals	/* - deprecated */
    oid         atttyparg	/* - deprecated */
    int2        attlen	/* attribute length, in bytes
			   -1=variable */
    int2        attnum	/* attribute number
			   >0=user attribute
			   <0=system attribute */
    int2        attbound	/* - deprecated */
    bool        attbyval	/* type passed by value? */
    bool        attcanindex	/* - deprecated */
    oid         attproc	/* - deprecated */
    int4        attnelems	/* # of array dimensions */
    int4        attcacheoff	/* cached offset into tuple */
    bool        attisset	/* is attribute set-valued? */
pg_inherits
    oid         inhrel	/* child class */
    oid         inhparent	/* parent class */
    int4        inhseqno	/* - deprecated */
    oid         indexrelid	/* oid of secondary index class */
    oid         indrelid	/* oid of indexed heap class */
    oid         indproc	/* function to compute index key from
				   attribute(s) in heap
				   0=not a functional index */
    int28       indkey	/* attribute numbers of key
			   attribute(s) */
    oid8        indclass	/* opclass of each key */
    bool        indisclustered	/* is the index clustered?
				   - unused */
    bool        indisarchived	/* is the index archival?
				   - unused */
    text        indpred	/* query plan for partial index
			   predicate */
pg_type
    NameData      typname	/* type name */
    oid         typowner	/* usesysid of owner */
    int2        typlen	/* length in internal form
			   -1=variable-length */
    int2        typprtlen	/* length in external form */
    bool        typbyval	/* type passed by value? */
    char        typtype	/* kind of type:
			   c=catalog (composite)
			   b=base */
    bool        typisdefined	/* defined or still a shell? */
    char        typdelim	/* delimiter for array external form */
    oid         typrelid	/* class (if composite) */
    oid         typelem	/* type of each array element */
    regproc     typinput	/* external-internal conversion
				   function */
    regproc     typoutput	/* internal-external conversion
				   function */
    regproc     typreceive	/* client-server conversion function */
    regproc     typsend	/* server-client conversion function */
    text        typdefault	/* default value */
pg_operator
    NameData      oprname	/* operator name */
    oid         oprowner	/* usesysid of owner */
    int2        oprprec	/* - deprecated */
    char        oprkind	/* kind of operator:
			   b=binary
			   l=left unary
			   r=right unary */
    bool        oprisleft	/* is operator left/right associative? */
    bool        oprcanhash	/* is operator usable for hashjoin? */
    oid         oprleft	/* left operand type */
    oid         oprright	/* right operand type */
    oid         oprresult	/* result type */
    oid         oprcom	/* commutator operator */
    oid         oprnegate	/* negator operator */
    oid         oprlsortop	/* sort operator for left operand */
    oid         oprrsortop	/* sort operator for right operand */
    regproc     oprcode	/* function implementing this operator */
    regproc     oprrest	/* function to calculate operator
			   restriction selectivity */
    regproc     oprjoin	/* function to calculate operator
			   join selectivity */
pg_opclass
    NameData      opcname	/* operator class name */
pg_proc
    NameData      proname	/* function name */
    oid         proowner	/* usesysid of owner */
    oid         prolang	/* function implementation language */
    bool        proisinh	/* - deprecated */
    bool        proistrusted	/* run in server or untrusted function
				   process? */
    bool        proiscachable	/* can the function return values be
				   cached? */
    int2        pronargs	/* # of arguments */
    bool        proretset	/* does the function return a set?
				   - unused */
    oid         prorettype	/* return type */
    oid8        proargtypes	/* argument types */
    int4        probyte_pct	/* % of argument size (in bytes) that
				   needs to be examined in order to
				   compute the function */
    int4        properbyte_cpu	/* sensitivity of the function's
				   running time to the size of its
				   inputs */
    int4        propercall_cpu	/* overhead of the function's
				   invocation (regardless of input
				   size) */
    int4        prooutin_ratio	/* size of the function's output as a
				   percentage of the size of the input */
    text        prosrc	/* function definition:
			   INTERNAL function: actual C name of function
			   C function: currently, this field is unused
			   SQL function: text of query(s)
			   PL function: text in procedural language */
    bytea       probin	/* path to object file (C functions only) */
pg_language
    NameData      lanname	/* language name */
    text        lancompiler	/* - deprecated */

ENTITIES
pg_database
    NameData      datname		/* database name */
    oid         datdba		/* usesysid of database administrator */
    text        datpath		/* directory of database under
				   $PGDATA */
pg_group
    NameData      groname	/* group name */
    int2        grosysid	/* group's UNIX group id */
    int2        grolist[1]	/* list of usesysids of group members */
pg_shadow
    NameData      usename		/* user's name */
    int2        usesysid	/* user's UNIX user id */
    bool        usecreatedb	/* can user create databases? */
    bool        usetrace	/* can user set trace flags? */
    bool        usesuper	/* can user be POSTGRES superuser? */
    bool        usecatupd	/* can user update catalogs? */

RULE SYSTEM CATALOGS
pg_listener
    NameData      relname	/* class for which asynchronous
			   notification is desired */
    int4        listenerpid	/* process id of server corresponding
				   to a frontend program waiting for
				   asynchronous notification */
    int4        notification	/* whether an event notification for
				   this process id still pending */
pg_prs2rule
    NameData      prs2name	/* rule name */
    char        prs2eventtype	/* rule event type:
				   R=retrieve
				   U=update (replace)
				   A=append
				   D=delete */
    oid         prs2eventrel	/* class to which event applies */
    int2        prs2eventattr	/* attribute to which event applies */
    float8      necessary	/* - deprecated */
    float8      sufficient	/* - deprecated */
    text        prs2text	/* text of original rule definition */
pg_prs2plans
    oid         prs2ruleid	/* prs2rule instance for which this
				   plan is used */
    int2        prs2planno	/* plan number (one rule may invoke
				   multiple plans) */
    text        prs2code	/* external representation of the plan */
pg_prs2stub
    oid         prs2relid	/* class to which this rule applies */
    bool        prs2islast	/* is this the last stub fragment? */
    int4        prs2no		/* stub fragment number */
    stub        prs2stub	/* stub fragment */
pg_rewrite
    NameData      rulename	/* rule name */
    char        ev_type	/* event type:
			   RETRIEVE, REPLACE, APPEND, DELETE
			   codes are parser-dependent (!?) */
    oid         ev_class	/* class to which this rule applies */
    int2        ev_attr	/* attribute to which this rule applies */
    bool        is_instead	/* is this an "instead" rule? */
    text        ev_qual	/* qualification with which to modify
			   (rewrite) the plan that triggered this
			   rule */
    text        action	/* parse tree of action */

LARGE OBJECT CATALOGS
pg_lobj
    oid         ourid		/* 'ourid' from pg_naming that
				   identifies this object in the
				   Inversion file system namespace */
    int4        objtype		/* storage type code:
				   0=Inversion
				   1=Unix
				   2=External
				   3=Jaquith */
    bytea       object_descripto/* opaque object-handle structure */
pg_naming
    NameData      filename	/* filename component */
    oid         ourid		/* random oid used to identify this
				   instance in other instances (can't
				   use the actual oid for obscure
				   reasons */
    oid         parentid	/* pg_naming instance of parent
				   Inversion file system directory */
pg_platter
     NameData     plname		/* platter name */
     int4       plstart		/* the highest OCCUPIED extent */
pg_plmap
     oid        plid		/* platter (in pg_platter) on which
				   this extent (of blocks) resides */
     oid        pldbid		/* database of the class to which this
				   extent (of blocks) belongs */
     oid        plrelid		/* class to which this extend (of
				   blocks) belongs */
     int4       plblkno		/* starting block number within the
				   class */
     int4       ploffset	/* offset within the platter at which
				   this extent begins */
     int4       plextentsz	/* length of this extent */