Having the command type be a part of the command ID isn't needed anywhere. Removing this simplifies the way we generate IDs in general, because we don't need Prepend() anymore.
The command type was only needed to prevent ID collisions within the command_envvar and command_argument tables. Those tables have since been separated into {check,event,notification}command_envvar and {check,event,notification}command_argument tables.
PR #9036 introduces some incompatible changes to the Redis schema, most
importantly where Icinga DB has to read the environment from: now it has to use
a new top-level key of the icinga:stats message instead of a value in the
IcingaApplication part of that message.
In order to avoid changes to the environment ID, it is now no longer derived
from the Environment constant but instead from the public key of the CA
certificate. This ensures that it is different between clusters by default, so
no additional changes have to be done to allow two clusters to use Icinga DB to
write into the same database.
To prevent the ID from changing when the CA certificate is replaced, it is also
persisted into the file /var/lib/icinga2/icingadb.env, so if that file exists,
it takes precedence over the CA certificate.
... i.e. UUID -> SHA1(env, eventType, x...) given that SHA1(env, x...) = type-specific ID.
Rationale: allow both masters to write the same history concurrently (while not
in split-brain), so that REPLACE INTO deduplicates the same events written twice.
* ack: SHA1(env, "ack_set"|"ack_clear", checkable.name, setTime)
* comment: SHA1(env, "comment_add"|"comment_remove", comment.name)
* downtime: SHA1(env, "downtime_start"|"downtime_end", downtime.name)
* flapping: SHA1(env, "flapping_start"|"flapping_end", checkable.name, startTime)
* notification: SHA1(env, "notification", notification.name, notificationType, sendTime)
* state: SHA1(env, "state_change", checkable.name, changeTime)
... i.e. UUID -> SHA1(x..., send time) given that SHA1(x...) = notification id.
Rationale: allow both masters to write the same notification history concurrently (while
not in split-brain), so that REPLACE INTO deduplicates the same events written twice.
... i.e. UUID -> SHA1(x..., check time) given that SHA1(x...) = checkable id.
Rationale: allow both masters to write the same state history concurrently (while
not in split-brain), so that REPLACE INTO deduplicates the same events written twice.
IdoPgsqlConnection::Escape() internally uses PQescapeStringConn() and its
documentation states the following:
Furthermore, PQescapeStringConn does not generate the single quotes that must
surround PostgreSQL string literals; they should be provided in the SQL
command that the result is inserted into.
So it's intended to use the result in 'string' literals, not in E'string'
literals as Icinga did. This results in problems as the behavior of
PQescapeStringConn() depends on how the current connection will interpret
regular single quoted literals, namely on the value of the
standard_conforming_strings variable.
The E'string' literals were initially introduced in
ac6f3f8acf4f52adedc7908db6452ed6da273ad7 to fix#1206 where PostgreSQL started
warning about escape sequences in string literals not supported by the SQL
standard (but by PostgreSQL depending on the value of
standard_conforming_strings). In the meantime the oldest PostgreSQL version on
any platform supported by Icinga increased to 9.2 (CentOS 7) and starting with
9.1, standard_conforming_strings is enabled by default, so there will be no
warnings about escape sequences (as the warning is only issued if the escape
sequence is actually interpreted by PostgreSQL).
