Memory Pool Types

By: Ben Matterson

Abstract: A description of the types of memory pools that might be found in TMP$POOLS.TMP$TYP.

I'm looking at the temporary table TMP$POOLS. The field TMP$TYPE has a bunch of abbreviations in it. What do those abbreviations mean? Here are the memory pool types represented by the values in TMP$POOLS.TMP$TYP:
  • CCH - Memory pool from which cache manager data structures are allocated. The major memory allocation is for the page buffers.
  • DYN - internal request pools specifically having to do with data definition (DDL) operations.
  • IRQ - Registry of persistent internal requests [Note: a "request" is the compiled form of a query]. InterBase executes internal requests against system tables to maintain and load a database's metadata
  • PRM - permanent pool from which internal metadata structures are allocated
  • REQ - Request blocks. Normal user queries which have been compiled into executable requests.
  • TRA - Transaction manager. Transaction pools allocate data structures having to do with a transaction such as savepoints and transaction bitmaps for concurrency control.
  • TRG - trigger pool from which a trigger request is allocated.

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