diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/catalog/README | 7 | ||||
| -rw-r--r-- | src/backend/storage/lmgr/README | 12 |
2 files changed, 10 insertions, 9 deletions
diff --git a/src/backend/catalog/README b/src/backend/catalog/README index f2221a75342..26dac4892af 100644 --- a/src/backend/catalog/README +++ b/src/backend/catalog/README @@ -1,7 +1,8 @@ -$Header: /cvsroot/pgsql/src/backend/catalog/README,v 1.5 2002/04/08 22:09:05 tgl Exp $ +$Header: /cvsroot/pgsql/src/backend/catalog/README,v 1.6 2002/04/15 23:46:13 momjian Exp $ -This directory contains .c files that manipulate the system catalogs -as well as .h files that define the structure of the system catalogs. +This directory contains .c files that manipulate the system catalogs; +src/include/catalog contains the .h files that define the structure +of the system catalogs. When the compile-time scripts (such as Gen_fmgrtab.sh and genbki.sh) execute, they grep the DATA statements out of the .h files and munge diff --git a/src/backend/storage/lmgr/README b/src/backend/storage/lmgr/README index 80cc7ce0608..a0fa7029069 100644 --- a/src/backend/storage/lmgr/README +++ b/src/backend/storage/lmgr/README @@ -1,4 +1,4 @@ -$Header: /cvsroot/pgsql/src/backend/storage/lmgr/README,v 1.9 2001/09/29 04:02:24 tgl Exp $ +$Header: /cvsroot/pgsql/src/backend/storage/lmgr/README,v 1.10 2002/04/15 23:46:13 momjian Exp $ LOCKING OVERVIEW @@ -93,7 +93,7 @@ grantMask - This bitmask indicates what types of locks are currently held on the given lockable object. It is used (against the lock table's conflict table) to determine if a new lock request will conflict with existing - lock types held. Conficts are determined by bitwise AND operations + lock types held. Conflicts are determined by bitwise AND operations between the grantMask and the conflict table entry for the requested lock type. Bit i of grantMask is 1 if and only if granted[i] > 0. @@ -268,7 +268,7 @@ Postgres' situation is a little more complex than the standard discussion of deadlock detection, for two reasons: 1. A process can be waiting for more than one other process, since there -might be multiple holders of (nonconflicting) lock types that all conflict +might be multiple holders of (non-conflicting) lock types that all conflict with the waiter's request. This creates no real difficulty however; we simply need to be prepared to trace more than one outgoing edge. @@ -292,7 +292,7 @@ algorithm. The workhorse of the deadlock detector is a routine FindLockCycle() which is given a starting point process (which must be a waiting process). -It recursively scans outwards across waits-for edges as discussed above. +It recursively scans outward across waits-for edges as discussed above. If it finds no cycle involving the start point, it returns "false". (As discussed above, we can ignore cycles not involving the start point.) When such a cycle is found, FindLockCycle() returns "true", and as it @@ -315,7 +315,7 @@ We build a proposed new queue order by doing a "topological sort" of the existing entries. Each soft edge that we are currently considering reversing creates a property of the partial order that the topological sort has to enforce. We must use a sort method that preserves the input -ordering as much as possible, so as not to gratuituously break arrival +ordering as much as possible, so as not to gratuitously break arrival order for processes not involved in a deadlock. (This is not true of the tsort method shown in Knuth, for example, but it's easily done by a simple doubly-nested-loop method that emits the first legal candidate at each @@ -406,7 +406,7 @@ implementation, BTW). Therefore, if ProcLockWakeup is always invoked after a lock is released or a wait queue is rearranged, there can be no failure to wake a wakable process. One should also note that LockWaitCancel (abort a waiter due to outside factors) must run -ProcLockWakeup, in case the cancelled waiter was soft-blocking other +ProcLockWakeup, in case the canceled waiter was soft-blocking other waiters. 4. We can minimize excess rearrangement-trial work by being careful to scan |