Mon Jan 16 15:33:05 PST 2006
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Brian A. Seklecki wrote: >All: > >One of the big things missing from the "Introduction" docs is a more >thorough explanation of "How Slony Works". As a DBA or SysAdmin, that's >the first question that I desire to have answered by a manual, and serves >to help me better understand all future operations and procedures, >especially troubleshooting. > > > Thanks, you're one of the first to do any "detailed criticism" of the docs... >For example, in introduction.html, it is stated "namely that Slony-I >operates using triggers", but what we should probably be saying is: > > "For every table, sequence, or database object that is replicated, Slony >is able to replicate changes by installing a trigger that catches updates, >inserts, and deletes." > >Also, "sl_log" isn't mentioned until Chapter/Page 3 and then again in 7. >However, no mention of the "_${repset}_cluster" schema is made at all >prior to that point. It's mentioned in Ch/Pg 5, but the purpose isn't >explained. Somewhere prior mention of "sl_log_1*", there should be a >paragraph explaining design: > > "For every database participating in replication, Slony creates a schema >named "_${repset}_cluster" at initialization time to maintain >configuration and status data. Most specifically, nodes acting as >master/sources maintain a _${repset}_cluster.sl_log_{1,2} table to >log/cache of all changes to master which are to be propagated to slaves." >(or something to that effect, check me) > > > That is in the section on defining clusters, now. >Also, it's also not explicitly stated anywhere that only Sequences and >Tables are replicated. Although that may seem rudimentary, a it's only >briefly touched on. > > > That is now explicitly mentioned in several places. >It should probably be explicitly stated: "A database consists of Casts, >Languages, Schemas, Tables, Indexes, Constraints, Sequences, Triggers, >Functions, Views, Types, etc.; however Slony only replicates Tables, >Indexes, and Sequences. All other objections constitute DDL changes that >must be manually replicated by the administrator." (or something to that >effect, check me). > > > I am a little reluctant to try to enumerate *all* types of database objects. Alan Perlis points out that if you have a procedure with 10 parameters, you probably have missed some :-). The same is likely true here. But I have revised the wording about DDL changes a bit to make it clearer what is and isn't replicated. >Another thing to add to the wishlist: Example real-world scenarios DBAs >may encountered and recommended procedures to follow. > > > There is a document called "addthings.sgml" to which I have been adding such of these scenarios as seem to come along. Beefing it up with "recipes" for how to do additional things is certainly fair game. >Also, it wouldn't hurt to break out XFig or Dia and add some explanatory >diagrams explaining concepts. > > I'm not much of a graphical person, which is why the paucity of diagrams... >Thoughts? > >(And yes, I'm will to help write docs!) >:} > > Now that I've changed these things, it looks like I need to do a bit of fiddling with the "man page" version :-(. Task for tomorrow... I have not yet checked all the changes in; I want to make sure I can cleanly run nsgmls on both slony.sgml and man.sgml (having some troubles at the moment). It'll go in tomorrow.
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