Sets the percentage of memory used as a merge threshold for an RLV-enabled table. If the
memory used surpasses the threshold, a merge will occur..
Default
0 (percent)
Note When RV_MERGE_TABLE_MEMPERCENT = 0, then the system uses a
(per-table) threshold of 100% / N, where N is the number of RLV-enabled tables that
have been loaded.
Scope
Option can be set at the database (PUBLIC) level
only.
Requires the SET ANY SYSTEM OPTION system privilege to set this option. Takes effect
immediately.
Remarks
An automated merge of the row-level versioned (RLV) store and IQ main stores occurs
based on the merge thresholds, including
RV_MERGE_TABLE_MEMPERCENT. If this table threshold is
exceeded, a merge will be triggered for the specific table
The system evaluates whether to merge the RLV and IQ main stores on a per-table
basis. It enumerates through all loaded RLV tables, and for each one decides
whether a merge is warranted. A merge for a single table is deemed warranted if:
- The table violates either the memory threshold
(RV_MERGE_TABLE_MEMPERCENT) or the row threshold (RV_MERGE_TABLE_NUMROWS),
and
- The system does not determine that a large percentage of the
RLV rows are uncommitted, and are therefore unable to be merged.