Comparison of general characteristics

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Prospective users must understand a few foundational details when comparing Oracle’s database with the EDB Postgres Advanced Server database. Having an understanding of these basic characteristics is especially valuable during discussions between Oracle experts and Postgres experts.


Before looking at the compatibility issues in detail, be aware that there are differences in nomenclature used in many SQL-based products. The table shows some of these differences.

OracleEDB Postgres Advanced Server
Table or indexTable, index, or relation
RowRow or tuple
ColumnColumn or attribute
Data blockPageWhen block is on disk
PageBufferWhen block is in memory

In addition, each instance of EDB Postgres Advanced Server is referred to as a cluster. A cluster is a collection of databases that is managed by a single program instance. It consists of a data directory that contains all data and configuration files. You can refer to it in two ways: by location of the data directory or by port number. A single server can have many program installations, and you can create multiple clusters.

General capabilities

Both Oracle and EDB Postgres Advanced Server are mature, enterprise-class, object-relational databases that meet the industry standards for atomicity, consistency, isolation, and durability (ACID) compliance. Both were developed from the same IBM research on System R and designed to solve many of the same problems. These database programs have many similarities.

General capabilitiesOracleEDB Postgres Advanced Server (EPAS)
Design originCommercial implementation based on IBM’s original research for System RAcademic implementation (UC Berkeley) based on IBM’s original research for System R
Continuous developmentSince 1979PostgreSQL development started in 1986. EPAS development started in 2004. EPAS is based on PostgreSQL and continuously merged.
Object relational databaseYesYes
Processing architectureProcess based and thread basedProcess based
Full ACID complianceYesYes
Multiversion concurrency controlYesYes
Multitenant architectureYesYes
Automatic workload managementYesNo
Enterprise database managementOracle Enterprise ManagerEDB Postgres Enterprise Manager
Multicore supportYesYes
Write-ahead durabilityRedo logsWrite-ahead log
Disk-read bufferingYesYes


When considering a new database, you need to understand whether a new solution has the capacity to support existing application data designs, workloads, and anticipated growth. Applying the capacity of a new solution to your workloads and future applications means understanding how it supports data across multiple structures in the database.

CapacitiesOracleEDB Postgres Advanced Server
Max. database sizeUnlimitedUnlimited
Max. table size4 GB x Block Size32 TB
Max. row size4 TB1.6 TB
Max. field sizeFor BLOB: (4 GB - 1) x DB_BLOCK_SIZE initialization parameter1 GB
Max. rows per tableUnlimitedUnlimited
Max. columns per table1000250 - 1600 depending on column types
Max. indexes per tableUnlimitedUnlimited

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