CHECKPOINT Statement

Syntax

CHECKPOINT

Usage

CHECKPOINT forces the database server to execute a checkpoint. Checkpoints are also performed automatically by the database server according to an internal algorithm. Applications do not normally need to issue CHECKPOINT.

SAP Sybase IQ uses checkpoints differently than OLTP databases such as SQL Anywhere. OLTP databases tend to have short transactions that affect only a small number of rows. Writing entire pages to disk would be very expensive for them. Instead, OLTP databases generally write to disk at checkpoints, and write only the changed data rows. SAP Sybase IQ is an OLAP database. A single OLAP transaction can change thousands or millions of rows of data. For this reason, the database server does not wait for a checkpoint to occur to perform physical writes. It writes updated data pages to disk after each transaction commits. For an OLAP database, writing full pages of data to disk is much more effective than writing small amounts of data at arbitrary checkpoints.

Adjusting the checkpoint time or issuing explicit checkpoints may be unnecessary. Controlling checkpoints is less important in SAP Sybase IQ than in OLTP database products, because SAP Sybase IQ writes the actual data pages after each transaction commits.

Standards

Permissions

Requires the CHECKPOINT system privilege.