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b060dbe000
Code review for0dc8ead463, prompted by a bug closed by91c40548d5. XLogReader's system for opening and closing segments had gotten too complicated, with callbacks being passed at both the XLogReaderAllocate level (read_page) as well as at the WALRead level (segment_open). This was confusing and hard to follow, so restructure things so that these callbacks are passed together at XLogReaderAllocate time, and add another callback to the set (segment_close) to make it a coherent whole. Also, ensure XLogReaderState is an argument to all the callbacks, so that they can grab at the ->private data if necessary. Document the whole arrangement more clearly. Author: Álvaro Herrera <alvherre@alvh.no-ip.org> Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Discussion: https://postgr.es/m/20200422175754.GA19858@alvherre.pgsql
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
/*-------------------------------------------------------------------------
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* logical.h
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* PostgreSQL logical decoding coordination
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*
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* Copyright (c) 2012-2020, PostgreSQL Global Development Group
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef LOGICAL_H
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#define LOGICAL_H
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#include "access/xlog.h"
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#include "access/xlogreader.h"
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#include "replication/output_plugin.h"
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#include "replication/slot.h"
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struct LogicalDecodingContext;
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typedef void (*LogicalOutputPluginWriterWrite) (struct LogicalDecodingContext *lr,
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XLogRecPtr Ptr,
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TransactionId xid,
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bool last_write
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);
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typedef LogicalOutputPluginWriterWrite LogicalOutputPluginWriterPrepareWrite;
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typedef void (*LogicalOutputPluginWriterUpdateProgress) (struct LogicalDecodingContext *lr,
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XLogRecPtr Ptr,
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TransactionId xid
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);
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typedef struct LogicalDecodingContext
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{
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/* memory context this is all allocated in */
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MemoryContext context;
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/* The associated replication slot */
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ReplicationSlot *slot;
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/* infrastructure pieces for decoding */
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XLogReaderState *reader;
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struct ReorderBuffer *reorder;
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struct SnapBuild *snapshot_builder;
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/*
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* Marks the logical decoding context as fast forward decoding one. Such a
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* context does not have plugin loaded so most of the following properties
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* are unused.
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*/
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bool fast_forward;
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OutputPluginCallbacks callbacks;
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OutputPluginOptions options;
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/*
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* User specified options
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*/
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List *output_plugin_options;
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/*
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* User-Provided callback for writing/streaming out data.
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*/
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LogicalOutputPluginWriterPrepareWrite prepare_write;
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LogicalOutputPluginWriterWrite write;
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LogicalOutputPluginWriterUpdateProgress update_progress;
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/*
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* Output buffer.
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*/
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StringInfo out;
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/*
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* Private data pointer of the output plugin.
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*/
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void *output_plugin_private;
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/*
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* Private data pointer for the data writer.
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*/
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void *output_writer_private;
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/*
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* State for writing output.
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*/
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bool accept_writes;
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bool prepared_write;
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XLogRecPtr write_location;
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TransactionId write_xid;
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} LogicalDecodingContext;
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extern void CheckLogicalDecodingRequirements(void);
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extern LogicalDecodingContext *CreateInitDecodingContext(char *plugin,
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List *output_plugin_options,
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bool need_full_snapshot,
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XLogRecPtr restart_lsn,
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XLogReaderRoutine *xl_routine,
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LogicalOutputPluginWriterPrepareWrite prepare_write,
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LogicalOutputPluginWriterWrite do_write,
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LogicalOutputPluginWriterUpdateProgress update_progress);
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extern LogicalDecodingContext *CreateDecodingContext(XLogRecPtr start_lsn,
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List *output_plugin_options,
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bool fast_forward,
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XLogReaderRoutine *xl_routine,
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LogicalOutputPluginWriterPrepareWrite prepare_write,
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LogicalOutputPluginWriterWrite do_write,
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LogicalOutputPluginWriterUpdateProgress update_progress);
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extern void DecodingContextFindStartpoint(LogicalDecodingContext *ctx);
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extern bool DecodingContextReady(LogicalDecodingContext *ctx);
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extern void FreeDecodingContext(LogicalDecodingContext *ctx);
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extern void LogicalIncreaseXminForSlot(XLogRecPtr lsn, TransactionId xmin);
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extern void LogicalIncreaseRestartDecodingForSlot(XLogRecPtr current_lsn,
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XLogRecPtr restart_lsn);
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extern void LogicalConfirmReceivedLocation(XLogRecPtr lsn);
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extern bool filter_by_origin_cb_wrapper(LogicalDecodingContext *ctx, RepOriginId origin_id);
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#endif
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