From be1aaed474578ee5076bf53c939164f507ab62e3 Mon Sep 17 00:00:00 2001 From: Mike Palmiotto Date: Wed, 4 Mar 2020 03:53:59 +0000 Subject: [PATCH 09/11] Move Backend-specific code down --- src/backend/postmaster/postmaster.c | 330 ++++++++++++++-------------- 1 file changed, 165 insertions(+), 165 deletions(-) diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index ceb738bf1e..f7a433f3a3 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -516,171 +516,6 @@ HANDLE PostmasterHandle; static Port *ConnProcPort = NULL; -/* - * BackendPrep - * - * Do all of the pre-fork setup for a new Backend. -*/ -int -BackendPrep(int argc, char *argv[]) -{ - /* - * Create backend data structure. Better before the fork() so we can - * handle failure cleanly. - */ - Backend *bn; - - bn = (Backend *) malloc(sizeof(Backend)); - if (!bn) - { - ereport(LOG, - (errcode(ERRCODE_OUT_OF_MEMORY), - errmsg("out of memory"))); - } - - /* - * Compute the cancel key that will be assigned to this backend. The - * backend will have its own copy in the forked-off process' value of - * MyCancelKey, so that it can transmit the key to the frontend. - */ - if (!RandomCancelKey(&MyCancelKey)) - { - free(bn); - ereport(LOG, - (errcode(ERRCODE_INTERNAL_ERROR), - errmsg("could not generate random cancel key"))); - } - - bn->cancel_key = MyCancelKey; - - /* Pass down canAcceptConnections state */ - ConnProcPort->canAcceptConnections = canAcceptConnections(BACKEND_TYPE_NORMAL); - bn->dead_end = (ConnProcPort->canAcceptConnections != CAC_OK && - ConnProcPort->canAcceptConnections != CAC_WAITBACKUP); - - /* - * Unless it's a dead_end child, assign it a child slot number - */ - if (!bn->dead_end) - bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot(); - else - bn->child_slot = 0; - - /* Hasn't asked to be notified about any bgworkers yet */ - bn->bgworker_notify = false; - - /* - * Push the Backend to the stack as-is so it can be retreived by the parent - * on the other side of the fork/exec. They will modify this entry in place. - */ - dlist_push_head(&BackendList, &bn->elem); - - return 0; -} - -/* - * BackendMain - * - * Child code when forking a Backend. - */ -void BackendMain(pg_attribute_unused() int argc, pg_attribute_unused() char *argv[]) -{ - /* - * Perform additional initialization and collect startup packet. - * - * We want to do this before InitProcess() for a couple of reasons: 1. - * so that we aren't eating up a PGPROC slot while waiting on the - * client. 2. so that if InitProcess() fails due to being out of - * PGPROC slots, we have already initialized libpq and are able to - * report the error to the client. - */ - BackendInitialize(ConnProcPort); - - /* And run the backend */ - BackendRun(ConnProcPort); /* does not return */ -} - -/* - * BackendPostmasterMain - * - * Parent code when forking a Backend. - */ -void BackendParentMain(pg_attribute_unused() int argc, pg_attribute_unused() char *argv[]) -{ - dlist_mutable_iter iter; - - /* - * Find our backend node by popping the element with a matching child slot - * off the list. This was pushed to the stack (incomplete) by BackendPrep. - * We need to fix it up and push back. - */ - dlist_foreach_modify(iter, &BackendList) - { - Backend *bp = dlist_container(Backend, elem, iter.cur); - - /* MyPMChildSlot is guaranteed to match the child MyPMChildSlot */ - if (bp->child_slot == MyPMChildSlot) - { - /* - * Everything's been successful, it's safe to add this backend to our list - * of backends. - */ - bp->pid = MyChildProcPid; - bp->bkend_type = BACKEND_TYPE_NORMAL; /* Can change later to WALSND */ - -#ifdef EXEC_BACKEND - if (!bp->dead_end) - ShmemBackendArrayAdd(bp); -#endif - break; /* There is only one entry and we've found it */ - } - } - - /* in parent, successful fork */ - ereport(DEBUG2, - (errmsg_internal("forked new backend, pid=%d socket=%d", - (int) MyChildProcPid, (int) MyProcPort->sock))); -} - -/* - * BackendCleanup - * - * Backend cleanup in case a failure occurs forking a new Backend. - */ -bool -BackendCleanup(int child_errno) -{ - dlist_mutable_iter iter; - - dlist_foreach_modify(iter, &BackendList) - { - Backend *bp = dlist_container(Backend, elem, iter.cur); - - if (bp->child_slot == MyPMChildSlot) - { - if (!bp->dead_end) - { - if (!ReleasePostmasterChildSlot(bp->child_slot)) - { - /* Could not release child slot! Panic! */ - return true; - } -#ifdef EXEC_BACKEND - ShmemBackendArrayRemove(bp); -#endif - } - dlist_delete(iter.cur); - free(bp); - break; - } - } - - report_fork_failure_to_client(MyProcPort, child_errno); - - /* Don't panic */ - return false; -} - /* * Postmaster main entry point */ @@ -3375,6 +3210,171 @@ reaper(SIGNAL_ARGS) errno = save_errno; } +/* + * BackendPrep + * + * Do all of the pre-fork setup for a new Backend. +*/ +int +BackendPrep(int argc, char *argv[]) +{ + /* + * Create backend data structure. Better before the fork() so we can + * handle failure cleanly. + */ + Backend *bn; + + bn = (Backend *) malloc(sizeof(Backend)); + if (!bn) + { + ereport(LOG, + (errcode(ERRCODE_OUT_OF_MEMORY), + errmsg("out of memory"))); + } + + /* + * Compute the cancel key that will be assigned to this backend. The + * backend will have its own copy in the forked-off process' value of + * MyCancelKey, so that it can transmit the key to the frontend. + */ + if (!RandomCancelKey(&MyCancelKey)) + { + free(bn); + ereport(LOG, + (errcode(ERRCODE_INTERNAL_ERROR), + errmsg("could not generate random cancel key"))); + } + + bn->cancel_key = MyCancelKey; + + /* Pass down canAcceptConnections state */ + ConnProcPort->canAcceptConnections = canAcceptConnections(BACKEND_TYPE_NORMAL); + bn->dead_end = (ConnProcPort->canAcceptConnections != CAC_OK && + ConnProcPort->canAcceptConnections != CAC_WAITBACKUP); + + /* + * Unless it's a dead_end child, assign it a child slot number + */ + if (!bn->dead_end) + bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot(); + else + bn->child_slot = 0; + + /* Hasn't asked to be notified about any bgworkers yet */ + bn->bgworker_notify = false; + + /* + * Push the Backend to the stack as-is so it can be retreived by the parent + * on the other side of the fork/exec. They will modify this entry in place. + */ + dlist_push_head(&BackendList, &bn->elem); + + return 0; +} + +/* + * BackendMain + * + * Child code when forking a Backend. + */ +void BackendMain(pg_attribute_unused() int argc, pg_attribute_unused() char *argv[]) +{ + /* + * Perform additional initialization and collect startup packet. + * + * We want to do this before InitProcess() for a couple of reasons: 1. + * so that we aren't eating up a PGPROC slot while waiting on the + * client. 2. so that if InitProcess() fails due to being out of + * PGPROC slots, we have already initialized libpq and are able to + * report the error to the client. + */ + BackendInitialize(ConnProcPort); + + /* And run the backend */ + BackendRun(ConnProcPort); /* does not return */ +} + +/* + * BackendPostmasterMain + * + * Parent code when forking a Backend. + */ +void BackendParentMain(pg_attribute_unused() int argc, pg_attribute_unused() char *argv[]) +{ + dlist_mutable_iter iter; + + /* + * Find our backend node by popping the element with a matching child slot + * off the list. This was pushed to the stack (incomplete) by BackendPrep. + * We need to fix it up and push back. + */ + dlist_foreach_modify(iter, &BackendList) + { + Backend *bp = dlist_container(Backend, elem, iter.cur); + + /* MyPMChildSlot is guaranteed to match the child MyPMChildSlot */ + if (bp->child_slot == MyPMChildSlot) + { + /* + * Everything's been successful, it's safe to add this backend to our list + * of backends. + */ + bp->pid = MyChildProcPid; + bp->bkend_type = BACKEND_TYPE_NORMAL; /* Can change later to WALSND */ + +#ifdef EXEC_BACKEND + if (!bp->dead_end) + ShmemBackendArrayAdd(bp); +#endif + break; /* There is only one entry and we've found it */ + } + } + + /* in parent, successful fork */ + ereport(DEBUG2, + (errmsg_internal("forked new backend, pid=%d socket=%d", + (int) MyChildProcPid, (int) MyProcPort->sock))); +} + +/* + * BackendCleanup + * + * Backend cleanup in case a failure occurs forking a new Backend. + */ +bool +BackendCleanup(int child_errno) +{ + dlist_mutable_iter iter; + + dlist_foreach_modify(iter, &BackendList) + { + Backend *bp = dlist_container(Backend, elem, iter.cur); + + if (bp->child_slot == MyPMChildSlot) + { + if (!bp->dead_end) + { + if (!ReleasePostmasterChildSlot(bp->child_slot)) + { + /* Could not release child slot! Panic! */ + return true; + } +#ifdef EXEC_BACKEND + ShmemBackendArrayRemove(bp); +#endif + } + dlist_delete(iter.cur); + free(bp); + break; + } + } + + report_fork_failure_to_client(MyProcPort, child_errno); + + /* Don't panic */ + return false; +} + /* * Scan the bgworkers list and see if the given PID (which has just stopped * or crashed) is in it. Handle its shutdown if so, and return true. If not a -- 2.21.0