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<TITLE>Data::Storage</TITLE> |
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<A NAME="__index__"></A> |
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<!-- INDEX BEGIN --> |
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<UL> |
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<LI><A HREF="#description">DESCRIPTION</A></LI> |
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<LI><A HREF="#requirements">REQUIREMENTS</A></LI> |
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<LI><A HREF="#authors / copyright">AUTHORS / COPYRIGHT</A></LI> |
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<LI><A HREF="#support / warranty">SUPPORT / WARRANTY</A></LI> |
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<LI><A HREF="#bugs">BUGS</A></LI> |
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<LI><A HREF="#user level errors">USER LEVEL ERRORS</A></LI> |
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<LI><A HREF="#mapping">Mapping</A></LI> |
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<LI><A HREF="#dbd::autocsv's rulebase">DBD::AutoCSV's rulebase</A></LI> |
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<LI><A HREF="#check structure of source node">Check structure of source node</A></LI> |
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<LI><A HREF="#modify structure of source node">Modify structure of source node</A></LI> |
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<LI><A HREF="#load source node by ident">Load source node by ident</A></LI> |
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</UL> |
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</UL> |
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</UL> |
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<LI><A HREF="#todo">TODO</A></LI> |
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<!-- INDEX END --> |
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<HR> |
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<H1><A NAME="description">DESCRIPTION</A></H1> |
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<P>Data::Transfer::Sync is a module providing a generic synchronization process |
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across arbitrary/multiple storages based on a ident/checksum mechanism. |
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It sits on top of Data::Storage.</P> |
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<H1><A NAME="requirements">REQUIREMENTS</A></H1> |
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<PRE> |
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For full functionality: |
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Data::Storage |
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Data::Transform |
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Data::Compare |
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... and all their dependencies</PRE> |
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<P> |
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<HR> |
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<H1><A NAME="authors / copyright">AUTHORS / COPYRIGHT</A></H1> |
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<P>The Data::Storage module is Copyright (c) 2002 Andreas Motl. |
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All rights reserved.</P> |
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<P>You may distribute it under the terms of either the GNU General Public |
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License or the Artistic License, as specified in the Perl README file.</P> |
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<P> |
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<HR> |
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<H1><A NAME="support / warranty">SUPPORT / WARRANTY</A></H1> |
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<P>Data::Storage is free software. IT COMES WITHOUT WARRANTY OF ANY KIND.</P> |
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<H1><A NAME="bugs">BUGS</A></H1> |
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<PRE> |
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When in "import" mode for windows file - DBD::AutoCSV may hang. |
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Hint: Maybe the source node contains an ident-, but no checksum column?</PRE> |
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<H1><A NAME="user level errors">USER LEVEL ERRORS</A></H1> |
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<H4><A NAME="mapping">Mapping</A></H4> |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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info: BizWorks::Process::Setup->syncResource( source_node Currency mode PULL erase 0 import 0 )critical: BizWorks::Process::Setup->startSync: Can't access mapping for node "Currency" - please check BizWorks::ResourceMapping. |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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You have to create a sub for each node used in synchronization inside named Perl module. The name of this sub _must_ match |
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the name of the node you want to sync. This sub holds mapping metadata to give the engine hints about how |
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to access the otherwise generic nodes. |
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- - - - - - - - - - - - - - - - - - - - - - - - - -</PRE> |
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<H4><A NAME="dbd::autocsv's rulebase">DBD::AutoCSV's rulebase</A></H4> |
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<PRE> |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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info: BizWorks::Process::Setup->syncResource( source_node Currency mode PULL erase 0 import 0 ) |
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info: Data::Transfer::Sync->syncNodes: source=L/Currency <- target=R/currencies.csv</PRE> |
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<PRE> |
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Execution ERROR: Error while scanning: Missing first row or scanrule not applied. at C:/home/amo/develop/netfrag.org/nfo/perl/libs/DBD/CSV.p |
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m line 165, <GEN9> line 1. |
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called from C:/home/amo/develop/netfrag.org/nfo/perl/libs/Data/Storage/Handler/DBI.pm at 123.</PRE> |
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DBI-Error: DBD::AutoCSV::st fetchrow_hashref failed: Attempt to fetch row from a Non-SELECT statement |
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notice: Data::Transfer::Sync->syncNodes: No nodes to synchronize. |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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DBD::AutoCSV contains a rulebase which is spooled down while attempting to guess the style of the csv file regarding |
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parameters like newline (eol), column-seperation-character (sep_char), quoting character (quote_char). |
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If this spool runs out of entries and no style could be resolved, DBD::CSV dies causing this "Execution ERROR" which |
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results in a "DBI-Error" afterwards. |
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- - - - - - - - - - - - - - - - - - - - - - - - - -</PRE> |
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<H4><A NAME="check structure of source node">Check structure of source node</A></H4> |
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<PRE> |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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info: Data::Transfer::Sync->syncNodes: source=L/Currency <- target=R/currencies.csv |
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critical: Data::Transfer::Sync->syncNodes: Can not synchronize: No ident found in source node, maybe try to "import" this node first. |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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If lowlevel detection succeeds, but no other required informations are found, this message is issued. |
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"Other informations" might be: |
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- column-header-row completely missing |
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- ident column is empty |
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- - - - - - - - - - - - - - - - - - - - - - - - - -</PRE> |
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<P> |
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<H4><A NAME="modify structure of source node">Modify structure of source node</A></H4> |
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<PRE> |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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info: Data::Transfer::Sync->syncNodes: source=L/Currency <- target=R/currencies.csv |
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info: Data::Transfer::Sync->_prepareNode_MetaProperties( descent source ) |
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warning: Data::Transfer::Sync->_prepareNode_MetaProperties: node is lacking meta properties - will try to alter... |
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SQL ERROR: Command 'ALTER' not recognized or not supported!</PRE> |
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<PRE> |
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SQL ERROR: Command 'ALTER' not recognized or not supported! |
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The Engine found a node which structure does not match the required. It tries to alter this automatically - only when doing "import" - |
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but the DBD driver (in this case DBD::CSV) gets in the way croaking not to be able to do this. |
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This could also appear if your database connection has insufficient rights to modify the database structure. |
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DBD::CSV croaks because it doesn't implement the ALTER command, so please edit your columns manually. |
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Hint: Add columns with the names of your "ident" and "checksum" property specifications. |
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- - - - - - - - - - - - - - - - - - - - - - - - - -</PRE> |
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<H4><A NAME="load source node by ident">Load source node by ident</A></H4> |
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<PRE> |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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info: Data::Transfer::Sync->_prepareNode_DummyIdent( descent source ) |
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pcritical: Data::Transfer::Sync->_modifyNode failed: "source" node is empty. |
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- - - - - - - - - - - - - - - - - - - - - - - - - - |
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The source node could not be loaded. Maybe the ident is missing. Please check manually. |
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Hint: Like above, the ident and/or checksum columns may be missing.... |
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- - - - - - - - - - - - - - - - - - - - - - - - - -</PRE> |
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<H1><A NAME="todo">TODO</A></H1> |
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<PRE> |
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- sub _resolveIdentProvider |
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- wrap _doModifySource and _doTransferTarget around a core function which can change virtually any type of node |
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- split this module up into Sync.pm, Sync/Core.pm, Sync/Compare.pm and Sync/Compare/Checksum.pm |
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- introduce _compareNodes as a core method and wrap it around methods in Sync/Compare/Checksum.pm |
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- introduce Sync/Compare/MyComparisonImplementation.pm |
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- some generic deferring method - e.g. "$self->defer(action)" - to be able to accumulate a bunch of actions for later processing |
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- this implies everything done is _really_ split up into generic actions - how else would we defer them??? |
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- example uses: |
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- fetch whole checksum list from node |
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- remember source ident retransmits |
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- remember: this is convenient - and maybe / of course faster - but we'll loose "per-node-atomic" operations |
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- feature: mechanism to implicit inject checksum property to nodes (alter table / modify schema) |
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- expand statistics / keep track of: |
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- touched/untouched nodes |
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- full sync |
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- just do a push and a pull for now but use stats for touched nodes in between to speed up things |
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- introduce some new metadata flags for a synchronization partner which is (e.g.) of "source" or "target": |
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- isNewNodePropagator |
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- isWriteProtected</PRE> |
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