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 |