CACHELEVEL1RESERVED

Read syntax diagramSkip visual syntax diagram CACHELEVEL1RESERVED=0size

Specifies the size, in megabytes, of the reserved portion of the Level 1 Db2® log cache that maintains records recently placed in the Db2 log.

InfoSphere® CDC can use two caches (Level 1 and Level 2) to improve performance when multiple subscriptions are used to replicate multiple streams of data at the same time.

The Level 1 cache resides in memory. This cache is used to rapidly retrieve Db2 log records during replication. The reserved part of this cache maintains records that have recently been placed in the Db2 log. This keyword determines how much of the Level 1 cache is used for this purpose. Allocating approximately 80% of the Level 1 cache for the reserved part should be the setting for most working environments. In addition, consider the following when setting the size of the reserved part of the Level 1 cache:

  • The size of the reserved part must be at least 5 megabytes. If you specify a size between 1 and 4 megabytes inclusively, InfoSphere CDC sets the size of the reserved part to 5 megabytes.
  • The size of the reserved part must occupy at least one block of the Level 1 cache. Otherwise, InfoSphere CDC sets the size of the reserved part to the default value for the CACHELEVEL1RESERVED keyword.
  • The size of the reserved part cannot occupy all blocks in the Level 1 cache. In other words, at least one block must be allocated for the other part of the cache. Otherwise, InfoSphere CDC sets the size of the reserved part to the default value for the CACHELEVEL1RESERVED keyword.
  • The size of the reserved part must be an exact multiple of the cache block size. If necessary, InfoSphere CDC sets the size of the reserved part by rounding down the CACHELEVEL1RESERVED keyword setting to the closest exact multiple of the cache block size.

If any of the keywords for defining the Level 1 and Level 2 caches (CACHEBLOCKSIZE, CACHELEVEL1RESERVED, and CACHELEVEL1SIZE) are set to zero, Db2 log records are not cached.

This keyword is optional.

Default Setting—0

Minimum Setting—5 MB