Help Center/ GaussDB(DWS)/ SQL Syntax Reference (8.1.3.x)/ Functions and Operators/ Residual File Management Functions/ Functions for Verifying Residual Files
Updated on 2024-12-19 GMT+08:00
View PDF

Functions for Verifying Residual Files

The pgxc residual file management function only operates on the CN and the current primary DN, and does not verify or clear residual files on the standby DN. Therefore, after the primary DN is cleared, you need to clear residual files on the standby DN or build the standby DN in a timely manner. This prevents residual files on the standby DN from being copied back to the primary DN due to incremental build after a primary/standby switchover.

pg_verify_residualfiles(filepath)

Description: Verifies whether the file recorded in the parameter specified file is a residual file. This function is an instance-level function and is related to the current database. It can run on any instance.

Parameter type: text

Return type: bool

The following table describes return columns.

Table 1 pg_verify_residualfiles (filepath) return fields

Column

Type

Description

isverified

bool

Verification completed or not

Example:

1
2
3
4
5
 
SELECT * FROM pg_verify_residualfiles('pgrf_20200908160211441546');
 isverified 
------------
 t
(1 row)

This function only verifies whether the recorded file is a residual file in the current database. If the recorded file is not in the current database, the verification is not applicable.

pg_verify_residualfiles()

Description: Verifies whether recorded files on all residual file lists of the current instance are residual files. This function is an instance-level function and is related to the current database. It can run on any instance.

Parameter type: none

Return type: record

The following table describes return columns.

Table 2 pg_verify_residualfiles () return fields

Column

Type

Description

result

bool

Verification completed or not

filepath

text

Residual file path

notes

text

Notes

Example:

1
2
3
4
5
 
SELECT * FROM pg_verify_residualfiles();
 result |         filepath          | notes 
--------+---------------------------+-------
 t      | pgrf_20200908160211441546 | 
(1 row)

This function only verifies whether the recorded file is a residual file in the current database. If the recorded file is not in the current database, the verification is not applicable.

pgxc_verify_residualfiles()

Description: Unified CN query function of pg_verify_residualfiles() This function is a cluster-level function and is related to the current database. It runs on CNs.

Parameter type: none

Return type: record

The following table describes return columns.

Table 3 pgxc_verify_residualfiles () return fields

Column

Type

Description

nodename

text

Node name

result

bool

Verification completed or not

filepath

text

Residual file path

notes

text

Notes

Example:

1
2
3
4
5
6
 
SELECT * FROM pgxc_verify_residualfiles();
   nodename   | result |         filepath          | notes 
--------------+--------+---------------------------+-------
 cn_5001      | t      | pgrf_20200910170129360401 | 
 dn_6001_6002 | t      | pgrf_20200908160211441546 | 
(2 rows)

This function only verifies whether the recorded file is a residual file in the current database. If the recorded file is not in the current database, the verification is not applicable.

pg_is_residualfiles(residualfile)

Description: Queries whether a specified relfilenode is a residual file in the current database. This function is an instance-level function and is related to the current database. It can run on any instance.

Parameter type: text

Return type: bool

The following table describes return columns.

Table 4 pg_is_residualfiles (residualfile) return fields

Column

Type

Description

result

bool

Residual file or not

Example:

1
2
3
4
5
 
SELECT * FROM pg_is_residualfiles('base/49155/114691');
 result 
--------
 t
(1 row)

This function only verifies whether the recorded file is a residual file in the current database. If the recorded file is not in the current database, it is verified as a residual file.

For example, the file base/15092/14790 is not regarded as a residual file in a gaussdb database, but it is regarded as a residual file in other databases.

SELECT * FROM pg_is_residualfiles('base/15092/14790');
result
--------
f
(1 row)

\c db2
db2=# SELECT * FROM pg_is_residualfiles('base/15092/14790');
result
--------
t
(1 row)