[ Newest version of patch applied.]
This patch is an updated version of the lock listing patch. I've made
the following changes:
- write documentation
- wrap the SRF in a view called 'pg_locks': all user-level
access should be done through this view
- re-diff against latest CVS
One thing I chose not to do is adapt the SRF to use the anonymous
composite type code from Joe Conway. I'll probably do that eventually,
but I'm not really convinced it's a significantly cleaner way to
bootstrap SRF builtins than the method this patch uses (of course, it
has other uses...)
Neil Conway
This commit is contained in:
Bruce Momjian
parent
f0ed4311b6
commit
82119a696e
@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/monitoring.sgml,v 1.10 2002/08/04 19:51:30 momjian Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/monitoring.sgml,v 1.11 2002/08/17 13:04:14 momjian Exp $
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-->
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<chapter id="monitoring">
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@ -543,6 +543,134 @@ FROM (SELECT pg_stat_get_backend_idset() AS backendid) AS S;
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</sect2>
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</sect1>
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<sect1 id="monitoring-locks">
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<title>Viewing Locks</title>
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<para>
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Another useful tool for monitoring database activity is the
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<literal>pg_locks</literal> system catalog. This allows the
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database administrator to view information about the outstanding
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locks in the lock manager. For example, this capability can be
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used to:
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<itemizedlist>
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<listitem>
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<para>
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View all the locks currently outstanding, all the locks on
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relations in a particular database, all the locks on a
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particular relation, or all the locks held by a particular
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<productname>PostgreSQL</productname> backend.
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</para>
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</listitem>
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<listitem>
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<para>
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View the relation in the current database with the most
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un-granted locks (which might be a source of contention among
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database clients).
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</para>
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</listitem>
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<listitem>
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<para>
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Determine the effect of lock contention on overall database
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performance, as well as the extent to which contention varies
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with overall database traffic.
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</para>
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</listitem>
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</itemizedlist>
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For more information on locking and managing concurrency with
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<productname>PostgreSQL</productname>, refer to the
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<citetitle>Administrator's Guide</citetitle>.
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</para>
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<note>
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<para>
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When the <literal>pg_locks</literal> view is accessed, an
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exclusive lock on an internal lock manager data structure must be
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acquired to ensure that the data produced by the view is
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consistent. The lock held on this structure conflicts with normal
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database operations, and can therefore have an effect on overall
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database performance. Nevertheless, the performance impact of
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accessing this view should be minimal in most situations.
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</para>
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</note>
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<para>
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The <literal>pg_locks</literal> view contains one row per
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lock. This means that if there are multiple locks on a single
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relation (which may or may not conflict with one another), a
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single relation may show up many times. Furthermore, only
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table-level locks are displayed (not row-level ones).
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</para>
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<table>
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<title>Lock Status System View</title>
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<tgroup cols="3">
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<thead>
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<row>
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<entry>Column Name</entry>
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<entry>Type</entry>
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<entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><structfield>relation</structfield></entry>
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<entry><type>oid</type></entry>
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<entry>The OID of the locked relation. When querying
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<literal>pg_locks</literal>, this column can be joined with the
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<literal>pg_class</literal> system catalog to get more
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information on the locked relation.</entry>
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</row>
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<row>
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<entry><structfield>database</structfield></entry>
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<entry><type>oid</type></entry>
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<entry>The OID of the database in which the locked relation
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exists. If the lock is on a globally-shared object, this value
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will be 0. When querying <literal>pg_locks</literal>, this
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column can be joined with the <literal>pg_database</literal>
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system catalog to get more information on the locked object's
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database.</entry>
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</row>
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<row>
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<entry><structfield>backendpid</structfield></entry>
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<entry><type>int4</type></entry>
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<entry>The process ID of the
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<productname>PostgreSQL</productname> backend that has
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acquired or is attempting to acquire the lock. If you have
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enabled the statistics collector, this column can be joined
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with the <literal>pg_stat_activity</literal> view to access
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more information on the backend holding or waiting to hold the
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lock.</entry>
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</row>
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<row>
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<entry><structfield>mode</structfield></entry>
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<entry><type>text</type></entry>
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<entry>The mode of the lock. For more information on the
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different lock modes available in
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<productname>PostgreSQL</productname>, refer to the
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<citetitle>User's Guide</citetitle>.</entry>
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</row>
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<row>
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<entry><structfield>isgranted</structfield></entry>
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<entry><type>text</type></entry>
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<entry>A boolean column indicating whether or not this
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particular lock has been granted. If the lock has not been
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granted, the backend atempting to acquire it will sleep until
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the lock is released (or a deadlock situation is detected). A
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single backend can be waiting to acquire at most one lock at
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any given time.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect1>
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</chapter>
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<!-- Keep this comment at the end of the file
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@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.26 2002/08/05 19:43:31 petere Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.27 2002/08/17 13:04:14 momjian Exp $
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-->
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<chapter id="mvcc">
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@ -408,7 +408,7 @@ ERROR: Can't serialize access due to concurrent update
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modes on the same table at the same time. (However, a transaction
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never conflicts with itself --- for example, it may acquire
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<literal>ACCESS EXCLUSIVE</literal> lock and later acquire
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<literal>ACCESS SHARE</literal> lock on the same table.) Nonconflicting
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<literal>ACCESS SHARE</literal> lock on the same table.) Non-conflicting
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lock modes may be held concurrently by many transactions. Notice in
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particular that some lock modes are self-conflicting (for example,
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<literal>ACCESS EXCLUSIVE</literal> cannot be held by more than one
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@ -417,6 +417,14 @@ ERROR: Can't serialize access due to concurrent update
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Once acquired, a lock mode is held till end of transaction.
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</para>
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<para>
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To examine a list of the currently outstanding locks in a
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database server, use the <literal>pg_locks</literal> system
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view. For more information on monitoring the status of the lock
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manager subsystem, refer to the <citetitle>Administrator's
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Guide</citetitle>.
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</para>
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<variablelist>
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<title>Table-level lock modes</title>
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<varlistentry>
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.111 2002/08/01 05:18:33 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.112 2002/08/17 13:04:14 momjian Exp $
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*
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* NOTES
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* Outside modules can create a lock table and acquire/release
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@ -1359,6 +1359,66 @@ LockShmemSize(int maxBackends)
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return size;
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}
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/*
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* GetLockStatusData - Return a summary of the lock manager's internal
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* status, for use in a user-level statistical reporting function.
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*
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* This function should be passed a pointer to a LockData struct. It fills
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* the structure with the appropriate information and returns. The goal
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* is to hold the LockMgrLock for as short a time as possible; thus, the
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* function simply makes a copy of the necessary data and releases the
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* lock, allowing the caller to contemplate and format the data for
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* as long as it pleases.
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*/
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void
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GetLockStatusData(LockData *data)
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{
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HTAB *holderTable;
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PROCLOCK *holder;
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HASH_SEQ_STATUS seqstat;
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int i = 0;
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data->currIdx = 0;
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LWLockAcquire(LockMgrLock, LW_EXCLUSIVE);
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holderTable = LockMethodTable[DEFAULT_LOCKMETHOD]->holderHash;
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data->nelements = holderTable->hctl->nentries;
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data->procs = (PGPROC *) palloc(sizeof(PGPROC) * data->nelements);
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data->locks = (LOCK *) palloc(sizeof(LOCK) * data->nelements);
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data->holders = (PROCLOCK *) palloc(sizeof(PROCLOCK) * data->nelements);
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hash_seq_init(&seqstat, holderTable);
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while ( (holder = hash_seq_search(&seqstat)) )
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{
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PGPROC *proc;
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LOCK *lock;
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/* Only do a shallow copy */
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proc = (PGPROC *) MAKE_PTR(holder->tag.proc);
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lock = (LOCK *) MAKE_PTR(holder->tag.lock);
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memcpy(&(data->procs[i]), proc, sizeof(PGPROC));
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memcpy(&(data->locks[i]), lock, sizeof(LOCK));
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memcpy(&(data->holders[i]), holder, sizeof(PROCLOCK));
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i++;
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}
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Assert(i == data->nelements);
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LWLockRelease(LockMgrLock);
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}
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char *
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GetLockmodeName(LOCKMODE mode)
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{
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Assert(mode <= MAX_LOCKMODES);
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return lock_mode_names[mode];
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}
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#ifdef LOCK_DEBUG
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/*
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@ -10,7 +10,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.171 2002/08/17 12:15:49 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.172 2002/08/17 13:04:15 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -239,8 +239,7 @@ ProcessUtility(Node *parsetree,
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break;
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/*
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* ******************************** portal manipulation ********************************
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*
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* ************************* portal manipulation ***************************
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*/
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case T_ClosePortalStmt:
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{
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@ -1,7 +1,7 @@
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#
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# Makefile for utils/adt
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#
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||||
# $Header: /cvsroot/pgsql/src/backend/utils/adt/Makefile,v 1.51 2001/10/04 04:13:40 ishii Exp $
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||||
# $Header: /cvsroot/pgsql/src/backend/utils/adt/Makefile,v 1.52 2002/08/17 13:04:15 momjian Exp $
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||||
#
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||||
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subdir = src/backend/utils/adt
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@ -17,7 +17,7 @@ endif
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|
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OBJS = acl.o arrayfuncs.o arrayutils.o bool.o cash.o char.o \
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||||
date.o datetime.o datum.o float.o format_type.o \
|
||||
geo_ops.o geo_selfuncs.o int.o int8.o like.o \
|
||||
geo_ops.o geo_selfuncs.o int.o int8.o like.o lockfuncs.o \
|
||||
misc.o nabstime.o name.o not_in.o numeric.o numutils.o \
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||||
oid.o oracle_compat.o \
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||||
regexp.o regproc.o ruleutils.o selfuncs.o sets.o \
|
||||
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||||
@ -27,7 +27,7 @@
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||||
# Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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||||
# Portions Copyright (c) 1994, Regents of the University of California
|
||||
#
|
||||
# $Header: /cvsroot/pgsql/src/bin/initdb/Attic/initdb.sh,v 1.166 2002/08/15 02:51:26 momjian Exp $
|
||||
# $Header: /cvsroot/pgsql/src/bin/initdb/Attic/initdb.sh,v 1.167 2002/08/17 13:04:15 momjian Exp $
|
||||
#
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||||
#-------------------------------------------------------------------------
|
||||
|
||||
@ -799,8 +799,6 @@ CREATE VIEW pg_views AS \
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||||
FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace) \
|
||||
WHERE C.relkind = 'v';
|
||||
|
||||
-- XXX why does pg_tables include sequences?
|
||||
|
||||
CREATE VIEW pg_tables AS \
|
||||
SELECT \
|
||||
N.nspname AS schemaname, \
|
||||
@ -1015,6 +1013,21 @@ CREATE VIEW pg_stat_database AS \
|
||||
pg_stat_get_db_blocks_hit(D.oid) AS blks_hit \
|
||||
FROM pg_database D;
|
||||
|
||||
CREATE VIEW pg_locks_result AS \
|
||||
SELECT \
|
||||
''::oid AS relation, \
|
||||
''::oid AS database, \
|
||||
''::int4 AS backendpid, \
|
||||
''::text AS mode, \
|
||||
NULL::bool AS isgranted;
|
||||
|
||||
UPDATE pg_proc SET \
|
||||
prorettype = (SELECT oid FROM pg_type \
|
||||
WHERE typname = 'pg_locks_result') \
|
||||
WHERE proname = 'pg_lock_status';
|
||||
|
||||
CREATE VIEW pg_locks AS SELECT * FROM pg_lock_status();
|
||||
|
||||
CREATE VIEW pg_settings AS \
|
||||
SELECT \
|
||||
A.name, \
|
||||
|
||||
@ -37,7 +37,7 @@
|
||||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $Id: catversion.h,v 1.149 2002/08/16 23:01:20 tgl Exp $
|
||||
* $Id: catversion.h,v 1.150 2002/08/17 13:04:15 momjian Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -53,6 +53,6 @@
|
||||
*/
|
||||
|
||||
/* yyyymmddN */
|
||||
#define CATALOG_VERSION_NO 200208161
|
||||
#define CATALOG_VERSION_NO 200208171
|
||||
|
||||
#endif
|
||||
|
||||
@ -7,7 +7,7 @@
|
||||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $Id: pg_proc.h,v 1.255 2002/08/16 23:01:20 tgl Exp $
|
||||
* $Id: pg_proc.h,v 1.256 2002/08/17 13:04:15 momjian Exp $
|
||||
*
|
||||
* NOTES
|
||||
* The script catalog/genbki.sh reads this file and generates .bki
|
||||
@ -2676,6 +2676,8 @@ DESCR("unary plus");
|
||||
DATA(insert OID = 1915 ( numeric_uplus PGNSP PGUID 12 f f t f i 1 1700 "1700" numeric_uplus - _null_ ));
|
||||
DESCR("unary plus");
|
||||
|
||||
DATA(insert OID = 1920 ( pg_lock_status PGNSP PGUID 12 f f f t v 0 0 "0" lock_status_srf - _null_ ));
|
||||
DESCR("view system lock information");
|
||||
DATA(insert OID = 1922 ( has_table_privilege PGNSP PGUID 12 f f t f s 3 16 "19 25 25" has_table_privilege_name_name - _null_ ));
|
||||
DESCR("user privilege on relation by username, rel name");
|
||||
DATA(insert OID = 1923 ( has_table_privilege PGNSP PGUID 12 f f t f s 3 16 "19 26 25" has_table_privilege_name_id - _null_ ));
|
||||
|
||||
@ -7,7 +7,7 @@
|
||||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $Id: lock.h,v 1.64 2002/08/01 05:18:34 momjian Exp $
|
||||
* $Id: lock.h,v 1.65 2002/08/17 13:04:18 momjian Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -203,6 +203,21 @@ typedef struct PROCLOCK
|
||||
#define PROCLOCK_LOCKMETHOD(holder) \
|
||||
(((LOCK *) MAKE_PTR((holder).tag.lock))->tag.lockmethod)
|
||||
|
||||
/*
|
||||
* This struct is used to encapsulate information passed from lmgr
|
||||
* internals to the lock listing statistical functions (lockfuncs.c).
|
||||
* It's just a convenient bundle of other lock.h structures. All
|
||||
* the information at a given index (holders[i], procs[i], locks[i])
|
||||
* is related.
|
||||
*/
|
||||
typedef struct
|
||||
{
|
||||
int nelements; /* The length of holders, procs, & locks */
|
||||
int currIdx; /* Current element being examined */
|
||||
PGPROC *procs;
|
||||
LOCK *locks;
|
||||
PROCLOCK *holders;
|
||||
} LockData;
|
||||
|
||||
/*
|
||||
* function prototypes
|
||||
@ -227,6 +242,8 @@ extern void RemoveFromWaitQueue(PGPROC *proc);
|
||||
extern int LockShmemSize(int maxBackends);
|
||||
extern bool DeadLockCheck(PGPROC *proc);
|
||||
extern void InitDeadLockChecking(void);
|
||||
extern void GetLockStatusData(LockData *data);
|
||||
extern char *GetLockmodeName(LOCKMODE mode);
|
||||
|
||||
#ifdef LOCK_DEBUG
|
||||
extern void DumpLocks(void);
|
||||
|
||||
@ -7,7 +7,7 @@
|
||||
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $Id: shmem.h,v 1.37 2002/06/20 20:29:52 momjian Exp $
|
||||
* $Id: shmem.h,v 1.38 2002/08/17 13:04:19 momjian Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -53,8 +53,7 @@ extern DLLIMPORT SHMEM_OFFSET ShmemBase;
|
||||
#define SHM_OFFSET_VALID(xx_offs)\
|
||||
(((xx_offs) != 0) && ((xx_offs) != INVALID_OFFSET))
|
||||
|
||||
|
||||
/* shmemqueue.c */
|
||||
/* shmqueue.c */
|
||||
typedef struct SHM_QUEUE
|
||||
{
|
||||
SHMEM_OFFSET prev;
|
||||
|
||||
@ -1268,6 +1268,8 @@ SELECT viewname, definition FROM pg_views ORDER BY viewname;
|
||||
--------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
||||
iexit | SELECT ih.name, ih.thepath, interpt_pp(ih.thepath, r.thepath) AS exit FROM ihighway ih, ramp r WHERE (ih.thepath ## r.thepath);
|
||||
pg_indexes | SELECT n.nspname AS schemaname, c.relname AS tablename, i.relname AS indexname, pg_get_indexdef(i.oid) AS indexdef FROM (((pg_index x JOIN pg_class c ON ((c.oid = x.indrelid))) JOIN pg_class i ON ((i.oid = x.indexrelid))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE ((c.relkind = 'r'::"char") AND (i.relkind = 'i'::"char"));
|
||||
pg_locks | SELECT pg_lock_status.relation, pg_lock_status."database", pg_lock_status.backendpid, pg_lock_status."mode", pg_lock_status.isgranted FROM pg_lock_status();
|
||||
pg_locks_result | SELECT 0::oid AS relation, 0::oid AS "database", 0 AS backendpid, ''::text AS "mode", NULL::boolean AS isgranted;
|
||||
pg_rules | SELECT n.nspname AS schemaname, c.relname AS tablename, r.rulename, pg_get_ruledef(r.oid) AS definition FROM ((pg_rewrite r JOIN pg_class c ON ((c.oid = r.ev_class))) LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))) WHERE (r.rulename <> '_RETURN'::name);
|
||||
pg_settings | SELECT a.name, a.setting FROM pg_show_all_settings() a;
|
||||
pg_stat_activity | SELECT d.oid AS datid, d.datname, pg_stat_get_backend_pid(s.backendid) AS procpid, pg_stat_get_backend_userid(s.backendid) AS usesysid, u.usename, pg_stat_get_backend_activity(s.backendid) AS current_query FROM pg_database d, (SELECT pg_stat_get_backend_idset() AS backendid) s, pg_shadow u WHERE ((pg_stat_get_backend_dbid(s.backendid) = d.oid) AND (pg_stat_get_backend_userid(s.backendid) = u.usesysid));
|
||||
@ -1305,7 +1307,7 @@ SELECT viewname, definition FROM pg_views ORDER BY viewname;
|
||||
shoelace_obsolete | SELECT shoelace.sl_name, shoelace.sl_avail, shoelace.sl_color, shoelace.sl_len, shoelace.sl_unit, shoelace.sl_len_cm FROM shoelace WHERE (NOT (EXISTS (SELECT shoe.shoename FROM shoe WHERE (shoe.slcolor = shoelace.sl_color))));
|
||||
street | SELECT r.name, r.thepath, c.cname FROM ONLY road r, real_city c WHERE (c.outline ## r.thepath);
|
||||
toyemp | SELECT emp.name, emp.age, emp."location", (12 * emp.salary) AS annualsal FROM emp;
|
||||
(39 rows)
|
||||
(41 rows)
|
||||
|
||||
SELECT tablename, rulename, definition FROM pg_rules
|
||||
ORDER BY tablename, rulename;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user