QCherry: Document upcoming 0.1.4 database recovery; organize wiki navigation

2026-09-19T10:51:46Z

Document upcoming 0.1.4 database recovery; organize wiki navigation

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= onDatabaseConnectionStateChange =
'''Available since 0.1.4 (in development; not present in public 0.1.3). Server-side event.'''

== Callback ==
<syntaxhighlight lang="lua">
function(connection, state, generation, errorCode, errorMessage)
</syntaxhighlight>

Delivered on the owning resource's Lua tick, including the initial connected transition. connection compares equal to the handle returned by dbConnect. State transitions include connected, reconnecting, disconnected and transaction_lost. The event is not broadcast to other resources or clients. Source is the owning resource root. Explicit close/shutdown does not promise a final event.

Each generation identifies a different native database session. Error details describe the transition; repeated retries in the same state need not produce additional events. Up to 256 state notifications are retained per resource, dropping oldest entries on overflow. Events describe history; [[dbGetConnectionState]] returns the latest snapshot.

<syntaxhighlight lang="lua">
addEventHandler("onDatabaseConnectionStateChange", resourceRoot,
function(connection, state, generation, errorCode, errorMessage)
if connection ~= db then return end
outputDebugString("DB " .. state .. ", generation=" .. generation)
end)
</syntaxhighlight>

Do not infer that a lost COMMIT failed. Do not blindly replay failed writes. See [[MySQL connection recovery]].
[[Category:Lua Events]]
[[Category:Server Events]]

OnDatabaseConnectionStateChange - Revision history

QCherry: Document upcoming 0.1.4 database recovery; organize wiki navigation