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Why are PostgreSQL data files bigger than data?
If you add up your data and indexes, you get your DB size: 28GB + 42GB = 70GB. Having big indexes means there’s a lot of extra disk space used. Index data is also cached in memory, so having big indexes means you may have two copies of indexed data in RAM, which means there’s less RAM for caching data on disk and you get more cache misses.
Where are the database files stored in PostgreSQL?
For each database in the cluster there is a subdirectory within PGDATA/base, named after the database’s OID in pg_database. This subdirectory is the default location for the database’s files; in particular, its system catalogs are stored there. Each table and index is stored in a separate file.
How are data files stored in a database?
Database File Layout This section describes the storage format at the level of files and directories. Traditionally, the configuration and data files used by a database cluster are stored together within the cluster’s data directory, commonly referred to as PGDATA (after the name of the environment variable that can be used to define it).
When to use segmented file names in PostgreSQL?
When a table or index exceeds 1 GB, it is divided into gigabyte-sized segments. The first segment’s file name is the same as the filenode; subsequent segments are named filenode.1, filenode.2, etc. This arrangement avoids problems on platforms that have file size limitations.
Is the date and time input accepted in PostgreSQL?
Date and time input is accepted in almost any reasonable format, including ISO 8601, SQL -compatible, traditional POSTGRES, and others. For some formats, ordering of day, month, and year in date input is ambiguous and there is support for specifying the expected ordering of these fields.
Which is the default date format for PostgreSQL?
The output format of the date/time types can be set to one of the four styles ISO 8601, SQL (Ingres), traditional POSTGRES (Unix date format), or German. The default is the ISO format. (The SQL standard requires the use of the ISO 8601 format.
What’s the default precision for interval in PostgreSQL?
By default, there is no explicit bound on precision. The allowed range of p is from 0 to 6 for the timestamp and interval types. Note: When timestamp values are stored as eight-byte integers (currently the default), microsecond precision is available over the full range of values.