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This code is intended as a demonstration of how the dynamic shared memory and dynamic background worker facilities can be used to establish a group of coooperating processes which can coordinate their activities using the shared memory message queue facility. By itself, the code does nothing particularly interesting: it simply allows messages to be passed through a loop of workers and back to the original process. But it's a useful unit test, in addition to its demonstration value.
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
/*--------------------------------------------------------------------------
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*
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* test_shm_mq.h
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* Definitions for shared memory message queues
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*
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* Copyright (C) 2013, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/test_shm_mq/test_shm_mq.h
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*
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* -------------------------------------------------------------------------
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*/
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#ifndef TEST_SHM_MQ_H
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#define TEST_SHM_MQ_H
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#include "storage/dsm.h"
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#include "storage/shm_mq.h"
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#include "storage/spin.h"
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/* Identifier for shared memory segments used by this extension. */
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#define PG_TEST_SHM_MQ_MAGIC 0x79fb2447
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/*
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* This structure is stored in the dynamic shared memory segment. We use
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* it to determine whether all workers started up OK and successfully
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* attached to their respective shared message queues.
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*/
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typedef struct
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{
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slock_t mutex;
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int workers_total;
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int workers_attached;
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int workers_ready;
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} test_shm_mq_header;
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/* Set up dynamic shared memory and background workers for test run. */
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extern void test_shm_mq_setup(uint64 queue_size, int32 nworkers,
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dsm_segment **seg, shm_mq_handle **output,
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shm_mq_handle **input);
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/* Main entrypoint for a worker. */
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extern void test_shm_mq_main(Datum);
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#endif
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