mirror of https://github.com/postgres/postgres
We've not found a use for this so far, and the current need, which is to convert the visibility map to a new format, does not suit the existing design anyway. So just rip it out. Author: Masahiko Sawada, slightly revised by me. Discussion: 20160215211313.GB31273@momjian.uspull/11/head
Robert Haas
10 years ago
parent
a93aec4e0f
commit
6f56b41ac0
@ -1,164 +0,0 @@ |
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/*
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* page.c |
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* |
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* per-page conversion operations |
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* |
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* Copyright (c) 2010-2016, PostgreSQL Global Development Group |
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* src/bin/pg_upgrade/page.c |
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*/ |
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#include "postgres_fe.h" |
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#include "pg_upgrade.h" |
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#include "storage/bufpage.h" |
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#ifdef PAGE_CONVERSION |
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static void getPageVersion( |
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uint16 *version, const char *pathName); |
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static pageCnvCtx *loadConverterPlugin( |
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uint16 newPageVersion, uint16 oldPageVersion); |
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/*
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* setupPageConverter() |
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* |
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* This function determines the PageLayoutVersion of the old cluster and |
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* the PageLayoutVersion of the new cluster. If the versions differ, this |
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* function loads a converter plugin and returns a pointer to a pageCnvCtx |
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* object (in *result) that knows how to convert pages from the old format |
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* to the new format. If the versions are identical, this function just |
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* returns a NULL pageCnvCtx pointer to indicate that page-by-page conversion |
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* is not required. |
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*/ |
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pageCnvCtx * |
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setupPageConverter(void) |
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{ |
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uint16 oldPageVersion; |
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uint16 newPageVersion; |
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pageCnvCtx *converter; |
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const char *msg; |
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char dstName[MAXPGPATH]; |
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char srcName[MAXPGPATH]; |
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snprintf(dstName, sizeof(dstName), "%s/global/%u", new_cluster.pgdata, |
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new_cluster.pg_database_oid); |
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snprintf(srcName, sizeof(srcName), "%s/global/%u", old_cluster.pgdata, |
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old_cluster.pg_database_oid); |
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getPageVersion(&oldPageVersion, srcName); |
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getPageVersion(&newPageVersion, dstName); |
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/*
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* If the old cluster and new cluster use the same page layouts, then we |
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* don't need a page converter. |
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*/ |
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if (newPageVersion != oldPageVersion) |
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{ |
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/*
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* The clusters use differing page layouts, see if we can find a |
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* plugin that knows how to convert from the old page layout to the |
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* new page layout. |
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*/ |
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if ((converter = loadConverterPlugin(newPageVersion, oldPageVersion)) == NULL) |
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pg_fatal("could not find plugin to convert from old page layout to new page layout\n"); |
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return converter; |
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} |
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else |
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return NULL; |
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} |
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/*
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* getPageVersion() |
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* |
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* Retrieves the PageLayoutVersion for the given relation. |
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* |
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* Returns NULL on success (and stores the PageLayoutVersion at *version), |
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* if an error occurs, this function returns an error message (in the form |
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* of a null-terminated string). |
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*/ |
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static void |
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getPageVersion(uint16 *version, const char *pathName) |
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{ |
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int relfd; |
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PageHeaderData page; |
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ssize_t bytesRead; |
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if ((relfd = open(pathName, O_RDONLY, 0)) < 0) |
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pg_fatal("could not open relation %s\n", pathName); |
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if ((bytesRead = read(relfd, &page, sizeof(page))) != sizeof(page)) |
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pg_fatal("could not read page header of %s\n", pathName); |
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*version = PageGetPageLayoutVersion(&page); |
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close(relfd); |
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return; |
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} |
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/*
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* loadConverterPlugin() |
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* |
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* This function loads a page-converter plugin library and grabs a |
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* pointer to each of the (interesting) functions provided by that |
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* plugin. The name of the plugin library is derived from the given |
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* newPageVersion and oldPageVersion. If a plugin is found, this |
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* function returns a pointer to a pageCnvCtx object (which will contain |
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* a collection of plugin function pointers). If the required plugin |
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* is not found, this function returns NULL. |
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*/ |
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static pageCnvCtx * |
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loadConverterPlugin(uint16 newPageVersion, uint16 oldPageVersion) |
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{ |
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char pluginName[MAXPGPATH]; |
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void *plugin; |
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/*
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* Try to find a plugin that can convert pages of oldPageVersion into |
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* pages of newPageVersion. For example, if we oldPageVersion = 3 and |
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* newPageVersion is 4, we search for a plugin named: |
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* plugins/convertLayout_3_to_4.dll |
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*/ |
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/*
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* FIXME: we are searching for plugins relative to the current directory, |
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* we should really search relative to our own executable instead. |
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*/ |
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snprintf(pluginName, sizeof(pluginName), "./plugins/convertLayout_%d_to_%d%s", |
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oldPageVersion, newPageVersion, DLSUFFIX); |
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if ((plugin = pg_dlopen(pluginName)) == NULL) |
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return NULL; |
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else |
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{ |
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pageCnvCtx *result = (pageCnvCtx *) pg_malloc(sizeof(*result)); |
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result->old.PageVersion = oldPageVersion; |
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result->new.PageVersion = newPageVersion; |
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result->startup = (pluginStartup) pg_dlsym(plugin, "init"); |
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result->convertFile = (pluginConvertFile) pg_dlsym(plugin, "convertFile"); |
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result->convertPage = (pluginConvertPage) pg_dlsym(plugin, "convertPage"); |
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result->shutdown = (pluginShutdown) pg_dlsym(plugin, "fini"); |
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result->pluginData = NULL; |
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/*
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* If the plugin has exported an initializer, go ahead and invoke it. |
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*/ |
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if (result->startup) |
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result->startup(MIGRATOR_API_VERSION, &result->pluginVersion, |
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newPageVersion, oldPageVersion, &result->pluginData); |
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return result; |
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} |
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} |
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#endif |
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