Write-Ahead Log / Settings server parameters - Azure Database for PostgreSQL - Flexible Server

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_init_zero

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes zeroes to new WAL files before first use.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_init_zero

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_recycle

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Recycles WAL files by renaming them.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_recycle

wal_skip_threshold

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Minimum size of new file to fsync instead of writing WAL.
Data type	integer
Default value	`2048`
Allowed values	`2048`
Parameter type	read-only
Documentation	wal_skip_threshold

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_init_zero

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes zeroes to new WAL files before first use.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_init_zero

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_recycle

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Recycles WAL files by renaming them.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_recycle

wal_skip_threshold

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Minimum size of new file to fsync instead of writing WAL.
Data type	integer
Default value	`2048`
Allowed values	`2048`
Parameter type	read-only
Documentation	wal_skip_threshold

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_init_zero

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes zeroes to new WAL files before first use.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_init_zero

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_recycle

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Recycles WAL files by renaming them.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_recycle

wal_skip_threshold

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Minimum size of new file to fsync instead of writing WAL.
Data type	integer
Default value	`2048`
Allowed values	`2048`
Parameter type	read-only
Documentation	wal_skip_threshold

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_init_zero

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes zeroes to new WAL files before first use.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_init_zero

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_recycle

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Recycles WAL files by renaming them.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_recycle

wal_skip_threshold

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Size of new file to fsync instead of writing WAL.
Data type	integer
Default value	`2048`
Allowed values	`2048`
Parameter type	read-only
Documentation	wal_skip_threshold

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_init_zero

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes zeroes to new WAL files before first use.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_init_zero

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_recycle

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Recycles WAL files by renaming them.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	wal_recycle

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after

commit_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the delay in microseconds between transaction commit and flushing WAL to disk.
Data type	integer
Default value	`0`
Allowed values	`0-100000`
Parameter type	dynamic
Documentation	commit_delay

commit_siblings

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the minimum concurrent open transactions before performing commit_delay.
Data type	integer
Default value	`5`
Allowed values	`0-1000`
Parameter type	dynamic
Documentation	commit_siblings

fsync

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Forces synchronization of updates to disk.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	fsync

full_page_writes

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint.
Data type	boolean
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	full_page_writes

synchronous_commit

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the current transaction's synchronization level.
Data type	enumeration
Default value	`on`
Allowed values	`on`
Parameter type	read-only
Documentation	synchronous_commit

wal_buffers

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Sets the number of disk-page buffers in shared memory for WAL. Unit is 8kb.
Data type	integer
Default value	Depends on resources (vCores, RAM, or disk space) allocated to the server.
Allowed values	`-1-262143`
Parameter type	static
Documentation	wal_buffers

Azure-specific notes

The default value for the wal_buffers server parameter is calculated when you provision the instance of Azure Database for PostgreSQL flexible server, based on the product name that you select for its compute. Any subsequent changes of product selection to the compute that supports the flexible server won't have any effect on the default value for the wal_buffers server parameter of that instance.

Every time you change the product assigned to an instance, you should also adjust the value for the wal_buffers parameter according to the values in the following formula.

In virtual machines with up to 4 vCores, the value computed for wal_buffers is 2048.

In virtual machines with more than 4 vCores, the value computed for wal_buffers is 16384.

Based on the previous formula, the following table lists the values this server parameter would be set to depending on the amount of memory provisioned:

vCores	wal_buffers
1	2048
2	2048
4	2048
8	16384
12	16384
16	16384
20	16384
32	16384
48	16384
64	16384
96	16384

wal_compression

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Compresses full-page writes written in WAL file.
Data type	boolean
Default value	`on`
Allowed values	`on,off`
Parameter type	dynamic
Documentation	wal_compression

wal_level

Attribute	Value
Category	Write-Ahead Log / Settings
Description	It determines how much information is written to the WAL.
Data type	enumeration
Default value	`replica`
Allowed values	`replica,logical`
Parameter type	static
Documentation	wal_level

wal_log_hints

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Writes full pages to WAL when first modified after a checkpoint, even for a non-critical modification.
Data type	boolean
Default value	`off`
Allowed values	`off`
Parameter type	read-only
Documentation	wal_log_hints

wal_sync_method

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Selects the method used for forcing WAL updates to disk.
Data type	enumeration
Default value	`fdatasync`
Allowed values	`fdatasync`
Parameter type	read-only
Documentation	wal_sync_method

wal_writer_delay

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Time interval between WAL flushes performed by the WAL writer.
Data type	integer
Default value	`200`
Allowed values	`1-10000`
Parameter type	dynamic
Documentation	wal_writer_delay

wal_writer_flush_after

Attribute	Value
Category	Write-Ahead Log / Settings
Description	Amount of WAL written out by WAL writer that triggers a flush.
Data type	integer
Default value	`128`
Allowed values	`0-2147483647`
Parameter type	dynamic
Documentation	wal_writer_flush_after