pg_classThe catalog pg_class describes tables and other objects that have columns or are otherwise similar to a table. This includes indexes (but see also pg_index), sequences (but see also pg_sequence), views, materialized views, composite types, and TOAST tables; see relkind. Below, when we mean all of these kinds of objects we speak of “relations”. Not all of pg_class's columns are meaningful for all relation kinds.
Table 53.11. pg_class Columns
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Column Type Description |
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Row identifier |
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Name of the table, index, view, etc. |
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The OID of the namespace that contains this relation |
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The OID of the data type that corresponds to this table's row type, if any; zero for indexes, sequences, and toast tables, which have no |
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For typed tables, the OID of the underlying composite type; zero for all other relations |
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Owner of the relation |
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If this is a table or an index, the access method used (heap, B-tree, hash, etc.); otherwise zero (zero occurs for sequences, as well as relations without storage, such as views) |
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Name of the on-disk file of this relation; zero means this is a “mapped” relation whose disk file name is determined by low-level state |
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The tablespace in which this relation is stored. If zero, the database's default tablespace is implied. Not meaningful if the relation has no on-disk file, except for partitioned tables, where this is the tablespace in which partitions will be created when one is not specified in the creation command. |
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Size of the on-disk representation of this table in pages (of size |
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Number of live rows in the table. This is only an estimate used by the planner. It is updated by |
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Number of pages that are marked all-visible in the table's visibility map. This is only an estimate used by the planner. It is updated by |
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OID of the TOAST table associated with this table, zero if none. The TOAST table stores large attributes “out of line” in a secondary table. |
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True if this is a table and it has (or recently had) any indexes |
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True if this table is shared across all databases in the cluster. Only certain system catalogs (such as |
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Number of user columns in the relation (system columns not counted). There must be this many corresponding entries in |
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Number of |
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True if table has (or once had) rules; see |
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True if table has (or once had) triggers; see |
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True if table or index has (or once had) any inheritance children or partitions |
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True if table has row-level security enabled; see |
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True if row-level security (when enabled) will also apply to table owner; see |
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