Start/notes.ini Parameters/FTG_CHECK_THREAD_MAX_MEM

FTG_CHECK_THREAD_MAX_MEM

Parameter: FTG_CHECK_THREAD_MAX_MEM
Short description: Activates memory detection and memory monitoring of the GTR FT engine per search thread, allowing memory-hungry full-text searches to be identified early.

Profile

Parameter
FTG_CHECK_THREAD_MAX_MEM
Category
Performance / Memory
Component
Server
Available since
9.0.1 (older)
Supported versions
9.0.1, 10.0, 11.0, 12.0, 14.0, 14.5, 14.5.1
GUI equivalent
notes.ini only (no GUI)
Possible values
0 (default, no monitoring) / 1 (memory detection and monitoring active)

Description

With FTG_CHECK_THREAD_MAX_MEM=1, the GTR full-text subsystem (General Text Retrieval) enables memory detection and memory monitoring per FT search thread. This makes it possible to identify memory-hungry queries early, before they cause „Not enough memory for full text indexing or search" errors or server instability.
The parameter is part of the tuning family from HCL KB0038904. Combined with FTG_MAX_MB_PER_THREAD (hard limit per thread) and FTG_MAX_MEM_POOL × FTG_MB_PER_THREAD (global pool limit) it enables controlled memory management of the FT engine. Once active, Show Statistics FT on the server console returns additional per-thread memory metrics.

Example configuration

Default (parameter not set) — no additional monitoring:
FTG_CHECK_THREAD_MAX_MEM=0
Recommended diagnostic/tuning variant:
FTG_CHECK_THREAD_MAX_MEM=1
Classic combination to bound memory-hungry searches:
FTG_CHECK_THREAD_MAX_MEM=1
FTG_MAX_MB_PER_THREAD=100

Notes & pitfalls

  • Only effective on servers (FT engine).
  • Only the =1 switch enables the additional FT memory statistics; without it Show Statistics FT does not return per-thread memory values.
  • Mostly useful during tuning/troubleshooting phases; in steady state, use it together with FTG_MAX_MB_PER_THREAD as a hard limit.
  • Companion parameters: FTG_USE_SYS_MEMORY, FTG_MAX_MB_PER_THREAD, FTG_MAX_MEM_POOL, FTG_MB_PER_THREAD.
  • Monitoring: show stat FT.* on the server console.
  • Takes effect after a server restart (classic notes.ini parameter, read at boot).

Sources (HCL Product Documentation)