keeper: improve db start logic #401
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Unfortunately pg_ctl start changed behavior in postgresql 10: pg_ctl for postgres < 10 with -w will returns 0 also if the instance isn't ready to accept connections. Whle in postgres >= 10 it will return a non 0 exit code (1 like when the instance fails to start) making it impossible to distinguish between problems starting an instance (i.e. wrong parameters) or an instance started but not ready to accept connections. To work with all the versions and since we want to distinguish between a failed start and a started but not ready instance we are forced to not use pg_ctl and write part of its logic here (I hate to do this). Now PGManager.start method directly starts the instance using the "postgres" executable and waits 1 minute to see if the process starts (checking its pid file) or exits due to an error. It doesn't check if the instance is ready to accept connections. When needed this is done inside the keeper calling WaitReady.
sgotti
force-pushed
the
update_pg_start_wait_logic
branch
from
e2a3527
to
da6ba1a
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Unfortunately pg_ctl start changed behavior in postgresql 10:
pg_ctl for postgres < 10 with -w will returns 0 also if the instance isn't ready
to accept connections.
While in postgres >= 10 it will return a non 0 exit code (1 like when the
instance fails to start) making it impossible to distinguish between problems
starting an instance (i.e. wrong parameters) or an instance started but not
ready to accept connections.
To work with all the versions and since we want to distinguish between a failed
start and a started but not ready instance we are forced to not use pg_ctl and
write part of its logic here (I hate to do this).
Now PGManager.start method directly starts the instance using the "postgres"
executable and waits 1 minute to see if the process starts (checking its pid file)
or exits due to an error. It doesn't check if the instance is ready to accept
connections. When needed this is done inside the keeper calling WaitReady.