xact_memory index parameter

You can set a limit on the amount of memory that is used by basic text search operations. Restricting memory usage is useful if you have a low memory configuration. By default, the memory limit is set by the value of the SHMTOTAL configuration parameter.

xact_memory index parameter

1  xact_memory =
2.1 memory_size
2.2.1 K
2.2.1 M
2.2.1 G
2.1 unlimited
Element Description
memory_size A positive integer that represents the maximum amount of memory for bts index operations.

The default unit is bytes. To specify a different multiple of bytes, include one of the following letters at the end of the number:

  • K = Kilobytes
  • M = Megabytes
  • G = Gigabytes

For example, 5G sets the maximum memory usage to 5 gigabytes.

Usage

If any bts index operation requires more memory than the value of the xact_memory index parameter, the operation fails.

If the xact_memory index parameter is set to unlimited or is not included in the index, the memory limit is set by the value of the SHMTOTAL configuration parameter.

Example

For example, the following statement creates a bts index that limits the amount of memory for basic text search transactions to 5 GB:

CREATE INDEX books_bts ON books(book_data bts_lvarchar_ops) 
USING bts(xact_memory=5G) IN bts_sbspace;