WL#3735: Replication begin/end log markers
Affects: Server-Prototype Only — Status: Un-Assigned — Priority: Medium
SUMMARY ------- Clearify begin/end of statements in log. PROBLEMS -------- 1. Sending table map events for every statement is inefficient. It would be nice if we only had to send table map events when the table has been changed. 2. The first row-based event after a set of table map events does the locking of all tables. The current code is complicated since the first row-based event might be for a table that should be filtered away. Having the locking in a separate event, will simplify the filtering code of the row-based events. SOLUTION (Just a draft, needs more work) ---------------------------------------- 1. We need to clarify what the log should contain for the following four things happening on the master: a. Start transaction : This is a BEGIN query log event. We probably need to have this for all transactions. b. Start statement : This needs to somehow encode all tables used in the statement so that tables that use table locking can make the table locks. c. End statement : This is just a flag. d. End transaction : Currently coded as COMMIT or ROLLBACK query log events or XID events. 2. For each of these we need to specify exactly when the events/flags should be generated and when not (i.e. is it allowed to have implicitly marked begin/end markers?). OPEN ISSUES ----------- 1. How should the table map list be purged in the slave?
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