Skip to content

Document ELECTRIC_REPLICATION_IDLE_WAL_SIZE_CHECK_PERIOD and ELECTRIC_REPLICATION_IDLE_WAL_SIZE_THRESHOLD #3631

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
alco wants to merge 2 commits into
base: main
Choose a base branch
from
+26 −0
Open

Document ELECTRIC_REPLICATION_IDLE_WAL_SIZE_CHECK_PERIOD and ELECTRIC_REPLICATION_IDLE_WAL_SIZE_THRESHOLD #3631

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
260cc0d
Document ELECTRIC_REPLICATION_IDLE_WAL_SIZE_CHECK_PERIOD and ELECTRIC…
alco Dec 21, 2025
f41585e
Fix typos
alco Dec 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
26 changes: 26 additions & 0 deletions website/docs/api/config.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,32 @@ Once Electric reconnects and replication catches up, Postgres will automatically

</EnvVarConfig>

### ELECTRIC_REPLICATION_IDLE_WAL_SIZE_CHECK_PERIOD

<EnvVarConfig
name="ELECTRIC_REPLICATION_IDLE_WAL_SIZE_CHECK_PERIOD"
defaultValue="1hr"
example="180min">

Define the periodicity of checking the amount of WAL retained by Electric's replication slot when the database connections are scaled to zero.

Every time such check is due, Electric opens a one-off database connection (causing the database instance to wake up if it was sleeping) and compares the slot's `restart_lsn` with the current LSN of the database. If the difference exceeds `ELECTRIC_REPLICATION_IDLE_WAL_SIZE_THRESHOLD`, Electric wakes up the connection subsystem and resumes logical replication streaming.

Note that any modifications in the database (INSERTs, UPDATEs, DELETEs, etc) contribute to the WAL size and advance the current LSN forward. However, if the database instance remains mostly idle and scaled to zero, Electric would by default wake it up once an hour only for it to be scaled back down again a few minutes later.

</EnvVarConfig>

### ELECTRIC_REPLICATION_IDLE_WAL_SIZE_THRESHOLD

<EnvVarConfig
name="ELECTRIC_REPLICATION_IDLE_WAL_SIZE_THRESHOLD"
defaultValue="100MiB"
example="1GB">

Define the maximum size of retained WAL that Electric can still consider safe when deciding whether to wake up the connection subsystem from the scaled-down state. Only when the difference between Postgres' current LSN and Electric's replication slot's `restart_lsn` exceeds this threshold will Electric wake up the connection subsystem and resume logical replication streaming.

</EnvVarConfig>

### ELECTRIC_MANUAL_TABLE_PUBLISHING

<EnvVarConfig
Expand Down