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Updated on 2025-08-19 GMT+08:00
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GS_ILM_PARAM

GS_ILM_PARAM is a feature parameter table, which records the parameters related to the ILM feature, such as the control parameters of background scheduling.

Table 1 GS_ILM_PARAM columns

Name

Type

Description

idx

smallint

Parameter ID.

name

name

Parameter name.

value

double precision

Parameter value.
Table 2 GS_ILM_PARAM feature parameter range

Parameter ID

Parameter Value

Description

1

EXECUTION_INTERVAL

Specifies the frequency of executing an ADO task, in minutes. The default value is 15. The value is an integer or floating-point number greater than or equal to 1 and less than or equal to 2147483647. The value is rounded down.

2

RETENTION_TIME

Specifies the retention period of ADO-related history records, in days. The default value is 30. The value is an integer or floating-point number greater than or equal to 1 and less than or equal to 2147483647. The value is rounded down.

7

ENABLE

Status of background scheduling. This parameter cannot be modified using DBE_ILM_ADMIN.CUSTOMIZE_ILM. Use DBE_ILM_ADMIN.DISABLE_ILM or DBE_ILM_ADMIN.ENABLE_ILM to modify it.

11

POLICY_TIME

Specifies whether the time unit of ADO is day or second. The time unit second is used only for testing.

Value range:

  • 0 (default): The unit is day.
  • 1: The unit is second, which is generally used in test scenarios.

12

ABS_JOBLIMIT

Specifies the maximum number of ADO jobs generated by an ADO task. The default value is 10. The value is an integer or floating-point number greater than or equal to 0 and less than or equal to 2147483647. The value is rounded down.

13

JOB_SIZELIMIT

Specifies the maximum number of bytes that can be processed by a single ADO job. The unit is MB. The default value is 1024. The value is an integer or floating-point number greater than or equal to 0 and less than or equal to 2147483647. The value is rounded down.

14

WIND_DURATION

Specifies the maintenance window duration, in minutes. The default value is 240 minutes (4 hours). The value is an integer greater than or equal to 0 and less than 1440 (24 hours).

15

BLOCK_LIMITS

Specifies the upper limit of the instance-level row-store compression rate. The default value is 40. The value ranges from 0 to 10000, in block/ms, indicating the maximum number of blocks that can be compressed per millisecond. 0 indicates that the rate is not limited.

16

ENABLE_META_COMPRESSION

Specifies whether to enable header compression. The default value is 0 (disabled), and the value 1 indicates that header compression is enabled.

NOTE:

If this parameter is set to 1, the compression ratio is improved for tables with short rows (less data in a single row), but the performance of accessing compressed rows greatly deteriorates. If most tables in the database have long rows, you are advised not to enable this parameter.

17

SAMPLE_MIN

Minimum sampling step for constant encoding and equivalent encoding. The default value is 10. The value range is [1,100]. Decimals can be entered and will be automatically rounded down.

18

SAMPLE_MAX

Maximum sampling step for constant encoding and equivalent encoding. The default value is 10. The value range is [1,100]. Decimals can be entered and will be automatically rounded down.

19

CONST_PRIO

Constant encoding priority. The default value is 40. The value range is [0,100]. The value 100 indicates that constant encoding is disabled. Decimals can be entered and will be automatically rounded down.

20

CONST_THRESHOLD

Constant encoding threshold. The default value is 90. The value range is [1,100], indicating that constant encoding is performed when the proportion of constant values in a column exceeds the threshold. Decimals can be entered and will be automatically rounded down.

21

EQVALUE_PRIO

Equivalent encoding priority. The default value is 60. The value range is [0,100]. The value 100 indicates that equivalent encoding is disabled. Decimals can be entered and will be automatically rounded down.

22

EQVALUE_THRESHOLD

Equivalent encoding threshold. The default value is 80. The value range is [1,100], indicating that equivalent encoding is performed when the ratio of equal values in two columns exceeds the threshold. Decimals can be entered and will be automatically rounded down.

23

ENABLE_DELTA_ENCODE_SWITCH

Specifies whether to enable difference encoding. The default value is 1. The value 0 indicates that difference encoding is disabled, and the value 1 indicates that difference encoding is enabled. Decimals can be entered and will be automatically rounded down.

24

LZ4_COMPRESSION_LEVEL

LZ4 compression level. The default value is 0. The value range is [0,16]. Decimals can be entered and will be automatically rounded down.

25

ENABLE_LZ4_PARTIAL_DECOMPRESSION

Specifies whether to enable partial decompression. The default value is 1. The value 0 indicates that partial decompression is disabled, and the value 1 indicates that partial decompression is enabled. Decimals can be entered and will be automatically rounded down.
Parent topic: OLTP Table Compression