Computer Science
SYSTEM CATALOGS(INTRO) PostgreSQL SYSTEM CATALOGS(INTRO)
Section 7 - System Catalogs
DESCRIPTION
In this section we list each of the attributes of the sys-
tem 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 */
PostgreSQL 03/13/94 1
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