Write-Ahead Log / Settings
Članek 09/27/2024
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Povratne informacije
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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
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