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| <html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>F.2. amcheck — tools to verify table and index consistency</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="adminpack.html" title="F.1. adminpack — pgAdmin support toolpack" /><link rel="next" href="auth-delay.html" title="F.3. auth_delay — pause on authentication failure" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">F.2. amcheck — tools to verify table and index consistency</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="adminpack.html" title="F.1. adminpack — pgAdmin support toolpack">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules and Extensions">Up</a></td><th width="60%" align="center">Appendix F. Additional Supplied Modules and Extensions</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="auth-delay.html" title="F.3. auth_delay — pause on authentication failure">Next</a></td></tr></table><hr /></div><div class="sect1" id="AMCHECK"><div class="titlepage"><div><div><h2 class="title" style="clear: both">F.2. amcheck — tools to verify table and index consistency <a href="#AMCHECK" class="id_link">#</a></h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="amcheck.html#AMCHECK-FUNCTIONS">F.2.1. Functions</a></span></dt><dt><span class="sect2"><a href="amcheck.html#AMCHECK-OPTIONAL-HEAPALLINDEXED-VERIFICATION">F.2.2. Optional <em class="parameter"><code>heapallindexed</code></em> Verification</a></span></dt><dt><span class="sect2"><a href="amcheck.html#AMCHECK-USING-AMCHECK-EFFECTIVELY">F.2.3. Using <code class="filename">amcheck</code> Effectively</a></span></dt><dt><span class="sect2"><a href="amcheck.html#AMCHECK-REPAIRING-CORRUPTION">F.2.4. Repairing Corruption</a></span></dt></dl></div><a id="id-1.11.7.12.2" class="indexterm"></a><p> | |
| The <code class="filename">amcheck</code> module provides functions that allow you to | |
| verify the logical consistency of the structure of relations. | |
| </p><p> | |
| The B-Tree checking functions verify various <span class="emphasis"><em>invariants</em></span> in the | |
| structure of the representation of particular relations. The | |
| correctness of the access method functions behind index scans and | |
| other important operations relies on these invariants always | |
| holding. For example, certain functions verify, among other things, | |
| that all B-Tree pages have items in <span class="quote">“<span class="quote">logical</span>”</span> order (e.g., | |
| for B-Tree indexes on <code class="type">text</code>, index tuples should be in | |
| collated lexical order). If that particular invariant somehow fails | |
| to hold, we can expect binary searches on the affected page to | |
| incorrectly guide index scans, resulting in wrong answers to SQL | |
| queries. If the structure appears to be valid, no error is raised. | |
| </p><p> | |
| Verification is performed using the same procedures as those used by | |
| index scans themselves, which may be user-defined operator class | |
| code. For example, B-Tree index verification relies on comparisons | |
| made with one or more B-Tree support function 1 routines. See <a class="xref" href="xindex.html#XINDEX-SUPPORT" title="38.16.3. Index Method Support Routines">Section 38.16.3</a> for details of operator class support | |
| functions. | |
| </p><p> | |
| Unlike the B-Tree checking functions which report corruption by raising | |
| errors, the heap checking function <code class="function">verify_heapam</code> checks | |
| a table and attempts to return a set of rows, one row per corruption | |
| detected. Despite this, if facilities that | |
| <code class="function">verify_heapam</code> relies upon are themselves corrupted, the | |
| function may be unable to continue and may instead raise an error. | |
| </p><p> | |
| Permission to execute <code class="filename">amcheck</code> functions may be granted | |
| to non-superusers, but before granting such permissions careful consideration | |
| should be given to data security and privacy concerns. Although the | |
| corruption reports generated by these functions do not focus on the contents | |
| of the corrupted data so much as on the structure of that data and the nature | |
| of the corruptions found, an attacker who gains permission to execute these | |
| functions, particularly if the attacker can also induce corruption, might be | |
| able to infer something of the data itself from such messages. | |
| </p><div class="sect2" id="AMCHECK-FUNCTIONS"><div class="titlepage"><div><div><h3 class="title">F.2.1. Functions <a href="#AMCHECK-FUNCTIONS" class="id_link">#</a></h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term"> | |
| <code class="function">bt_index_check(index regclass, heapallindexed boolean) returns void</code> | |
| <a id="id-1.11.7.12.8.2.1.1.2" class="indexterm"></a> | |
| </span></dt><dd><p> | |
| <code class="function">bt_index_check</code> tests that its target, a | |
| B-Tree index, respects a variety of invariants. Example usage: | |
| </p><pre class="screen"> | |
| test=# SELECT bt_index_check(index => c.oid, heapallindexed => i.indisunique), | |
| c.relname, | |
| c.relpages | |
| FROM pg_index i | |
| JOIN pg_opclass op ON i.indclass[0] = op.oid | |
| JOIN pg_am am ON op.opcmethod = am.oid | |
| JOIN pg_class c ON i.indexrelid = c.oid | |
| JOIN pg_namespace n ON c.relnamespace = n.oid | |
| WHERE am.amname = 'btree' AND n.nspname = 'pg_catalog' | |
| -- Don't check temp tables, which may be from another session: | |
| AND c.relpersistence != 't' | |
| -- Function may throw an error when this is omitted: | |
| AND c.relkind = 'i' AND i.indisready AND i.indisvalid | |
| ORDER BY c.relpages DESC LIMIT 10; | |
| bt_index_check | relname | relpages | |
| ----------------+---------------------------------+---------- | |
| | pg_depend_reference_index | 43 | |
| | pg_depend_depender_index | 40 | |
| | pg_proc_proname_args_nsp_index | 31 | |
| | pg_description_o_c_o_index | 21 | |
| | pg_attribute_relid_attnam_index | 14 | |
| | pg_proc_oid_index | 10 | |
| | pg_attribute_relid_attnum_index | 9 | |
| | pg_amproc_fam_proc_index | 5 | |
| | pg_amop_opr_fam_index | 5 | |
| | pg_amop_fam_strat_index | 5 | |
| (10 rows) | |
| </pre><p> | |
| This example shows a session that performs verification of the | |
| 10 largest catalog indexes in the database <span class="quote">“<span class="quote">test</span>”</span>. | |
| Verification of the presence of heap tuples as index tuples is | |
| requested for the subset that are unique indexes. Since no | |
| error is raised, all indexes tested appear to be logically | |
| consistent. Naturally, this query could easily be changed to | |
| call <code class="function">bt_index_check</code> for every index in the | |
| database where verification is supported. | |
| </p><p> | |
| <code class="function">bt_index_check</code> acquires an <code class="literal">AccessShareLock</code> | |
| on the target index and the heap relation it belongs to. This lock mode | |
| is the same lock mode acquired on relations by simple | |
| <code class="literal">SELECT</code> statements. | |
| <code class="function">bt_index_check</code> does not verify invariants | |
| that span child/parent relationships, but will verify the | |
| presence of all heap tuples as index tuples within the index | |
| when <em class="parameter"><code>heapallindexed</code></em> is | |
| <code class="literal">true</code>. When a routine, lightweight test for | |
| corruption is required in a live production environment, using | |
| <code class="function">bt_index_check</code> often provides the best | |
| trade-off between thoroughness of verification and limiting the | |
| impact on application performance and availability. | |
| </p></dd><dt><span class="term"> | |
| <code class="function">bt_index_parent_check(index regclass, heapallindexed boolean, rootdescend boolean) returns void</code> | |
| <a id="id-1.11.7.12.8.2.2.1.2" class="indexterm"></a> | |
| </span></dt><dd><p> | |
| <code class="function">bt_index_parent_check</code> tests that its | |
| target, a B-Tree index, respects a variety of invariants. | |
| Optionally, when the <em class="parameter"><code>heapallindexed</code></em> | |
| argument is <code class="literal">true</code>, the function verifies the | |
| presence of all heap tuples that should be found within the | |
| index. When the optional <em class="parameter"><code>rootdescend</code></em> | |
| argument is <code class="literal">true</code>, verification re-finds | |
| tuples on the leaf level by performing a new search from the | |
| root page for each tuple. The checks that can be performed by | |
| <code class="function">bt_index_parent_check</code> are a superset of the | |
| checks that can be performed by <code class="function">bt_index_check</code>. | |
| <code class="function">bt_index_parent_check</code> can be thought of as | |
| a more thorough variant of <code class="function">bt_index_check</code>: | |
| unlike <code class="function">bt_index_check</code>, | |
| <code class="function">bt_index_parent_check</code> also checks | |
| invariants that span parent/child relationships, including checking | |
| that there are no missing downlinks in the index structure. | |
| <code class="function">bt_index_parent_check</code> follows the general | |
| convention of raising an error if it finds a logical | |
| inconsistency or other problem. | |
| </p><p> | |
| A <code class="literal">ShareLock</code> is required on the target index by | |
| <code class="function">bt_index_parent_check</code> (a | |
| <code class="literal">ShareLock</code> is also acquired on the heap relation). | |
| These locks prevent concurrent data modification from | |
| <code class="command">INSERT</code>, <code class="command">UPDATE</code>, and <code class="command">DELETE</code> | |
| commands. The locks also prevent the underlying relation from | |
| being concurrently processed by <code class="command">VACUUM</code>, as well as | |
| all other utility commands. Note that the function holds locks | |
| only while running, not for the entire transaction. | |
| </p><p> | |
| <code class="function">bt_index_parent_check</code>'s additional | |
| verification is more likely to detect various pathological | |
| cases. These cases may involve an incorrectly implemented | |
| B-Tree operator class used by the index that is checked, or, | |
| hypothetically, undiscovered bugs in the underlying B-Tree index | |
| access method code. Note that | |
| <code class="function">bt_index_parent_check</code> cannot be used when | |
| hot standby mode is enabled (i.e., on read-only physical | |
| replicas), unlike <code class="function">bt_index_check</code>. | |
| </p></dd></dl></div><div class="tip"><h3 class="title">Tip</h3><p> | |
| <code class="function">bt_index_check</code> and | |
| <code class="function">bt_index_parent_check</code> both output log | |
| messages about the verification process at | |
| <code class="literal">DEBUG1</code> and <code class="literal">DEBUG2</code> severity | |
| levels. These messages provide detailed information about the | |
| verification process that may be of interest to | |
| <span class="productname">PostgreSQL</span> developers. Advanced users | |
| may also find this information helpful, since it provides | |
| additional context should verification actually detect an | |
| inconsistency. Running: | |
| </p><pre class="programlisting"> | |
| SET client_min_messages = DEBUG1; | |
| </pre><p> | |
| in an interactive <span class="application">psql</span> session before | |
| running a verification query will display messages about the | |
| progress of verification with a manageable level of detail. | |
| </p></div><div class="variablelist"><dl class="variablelist"><dt><span class="term"> | |
| <code class="function"> | |
| verify_heapam(relation regclass, | |
| on_error_stop boolean, | |
| check_toast boolean, | |
| skip text, | |
| startblock bigint, | |
| endblock bigint, | |
| blkno OUT bigint, | |
| offnum OUT integer, | |
| attnum OUT integer, | |
| msg OUT text) | |
| returns setof record | |
| </code> | |
| </span></dt><dd><p> | |
| Checks a table, sequence, or materialized view for structural corruption, | |
| where pages in the relation contain data that is invalidly formatted, and | |
| for logical corruption, where pages are structurally valid but | |
| inconsistent with the rest of the database cluster. | |
| </p><p> | |
| The following optional arguments are recognized: | |
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">on_error_stop</code></span></dt><dd><p> | |
| If true, corruption checking stops at the end of the first block in | |
| which any corruptions are found. | |
| </p><p> | |
| Defaults to false. | |
| </p></dd><dt><span class="term"><code class="literal">check_toast</code></span></dt><dd><p> | |
| If true, toasted values are checked against the target relation's | |
| TOAST table. | |
| </p><p> | |
| This option is known to be slow. Also, if the toast table or its | |
| index is corrupt, checking it against toast values could conceivably | |
| crash the server, although in many cases this would just produce an | |
| error. | |
| </p><p> | |
| Defaults to false. | |
| </p></dd><dt><span class="term"><code class="literal">skip</code></span></dt><dd><p> | |
| If not <code class="literal">none</code>, corruption checking skips blocks that | |
| are marked as all-visible or all-frozen, as specified. | |
| Valid options are <code class="literal">all-visible</code>, | |
| <code class="literal">all-frozen</code> and <code class="literal">none</code>. | |
| </p><p> | |
| Defaults to <code class="literal">none</code>. | |
| </p></dd><dt><span class="term"><code class="literal">startblock</code></span></dt><dd><p> | |
| If specified, corruption checking begins at the specified block, | |
| skipping all previous blocks. It is an error to specify a | |
| <em class="parameter"><code>startblock</code></em> outside the range of blocks in the | |
| target table. | |
| </p><p> | |
| By default, checking begins at the first block. | |
| </p></dd><dt><span class="term"><code class="literal">endblock</code></span></dt><dd><p> | |
| If specified, corruption checking ends at the specified block, | |
| skipping all remaining blocks. It is an error to specify an | |
| <em class="parameter"><code>endblock</code></em> outside the range of blocks in the target | |
| table. | |
| </p><p> | |
| By default, all blocks are checked. | |
| </p></dd></dl></div><p> | |
| For each corruption detected, <code class="function">verify_heapam</code> returns | |
| a row with the following columns: | |
| </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">blkno</code></span></dt><dd><p> | |
| The number of the block containing the corrupt page. | |
| </p></dd><dt><span class="term"><code class="literal">offnum</code></span></dt><dd><p> | |
| The OffsetNumber of the corrupt tuple. | |
| </p></dd><dt><span class="term"><code class="literal">attnum</code></span></dt><dd><p> | |
| The attribute number of the corrupt column in the tuple, if the | |
| corruption is specific to a column and not the tuple as a whole. | |
| </p></dd><dt><span class="term"><code class="literal">msg</code></span></dt><dd><p> | |
| A message describing the problem detected. | |
| </p></dd></dl></div></dd></dl></div></div><div class="sect2" id="AMCHECK-OPTIONAL-HEAPALLINDEXED-VERIFICATION"><div class="titlepage"><div><div><h3 class="title">F.2.2. Optional <em class="parameter"><code>heapallindexed</code></em> Verification <a href="#AMCHECK-OPTIONAL-HEAPALLINDEXED-VERIFICATION" class="id_link">#</a></h3></div></div></div><p> | |
| When the <em class="parameter"><code>heapallindexed</code></em> argument to B-Tree | |
| verification functions is <code class="literal">true</code>, an additional | |
| phase of verification is performed against the table associated with | |
| the target index relation. This consists of a <span class="quote">“<span class="quote">dummy</span>”</span> | |
| <code class="command">CREATE INDEX</code> operation, which checks for the | |
| presence of all hypothetical new index tuples against a temporary, | |
| in-memory summarizing structure (this is built when needed during | |
| the basic first phase of verification). The summarizing structure | |
| <span class="quote">“<span class="quote">fingerprints</span>”</span> every tuple found within the target | |
| index. The high level principle behind | |
| <em class="parameter"><code>heapallindexed</code></em> verification is that a new | |
| index that is equivalent to the existing, target index must only | |
| have entries that can be found in the existing structure. | |
| </p><p> | |
| The additional <em class="parameter"><code>heapallindexed</code></em> phase adds | |
| significant overhead: verification will typically take several times | |
| longer. However, there is no change to the relation-level locks | |
| acquired when <em class="parameter"><code>heapallindexed</code></em> verification is | |
| performed. | |
| </p><p> | |
| The summarizing structure is bound in size by | |
| <code class="varname">maintenance_work_mem</code>. In order to ensure that | |
| there is no more than a 2% probability of failure to detect an | |
| inconsistency for each heap tuple that should be represented in the | |
| index, approximately 2 bytes of memory are needed per tuple. As | |
| less memory is made available per tuple, the probability of missing | |
| an inconsistency slowly increases. This approach limits the | |
| overhead of verification significantly, while only slightly reducing | |
| the probability of detecting a problem, especially for installations | |
| where verification is treated as a routine maintenance task. Any | |
| single absent or malformed tuple has a new opportunity to be | |
| detected with each new verification attempt. | |
| </p></div><div class="sect2" id="AMCHECK-USING-AMCHECK-EFFECTIVELY"><div class="titlepage"><div><div><h3 class="title">F.2.3. Using <code class="filename">amcheck</code> Effectively <a href="#AMCHECK-USING-AMCHECK-EFFECTIVELY" class="id_link">#</a></h3></div></div></div><p> | |
| <code class="filename">amcheck</code> can be effective at detecting various types of | |
| failure modes that <a class="link" href="app-initdb.html#APP-INITDB-DATA-CHECKSUMS"><span class="application">data | |
| checksums</span></a> will fail to catch. These include: | |
| </p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p> | |
| Structural inconsistencies caused by incorrect operator class | |
| implementations. | |
| </p><p> | |
| This includes issues caused by the comparison rules of operating | |
| system collations changing. Comparisons of datums of a collatable | |
| type like <code class="type">text</code> must be immutable (just as all | |
| comparisons used for B-Tree index scans must be immutable), which | |
| implies that operating system collation rules must never change. | |
| Though rare, updates to operating system collation rules can | |
| cause these issues. More commonly, an inconsistency in the | |
| collation order between a primary server and a standby server is | |
| implicated, possibly because the <span class="emphasis"><em>major</em></span> operating | |
| system version in use is inconsistent. Such inconsistencies will | |
| generally only arise on standby servers, and so can generally | |
| only be detected on standby servers. | |
| </p><p> | |
| If a problem like this arises, it may not affect each individual | |
| index that is ordered using an affected collation, simply because | |
| <span class="emphasis"><em>indexed</em></span> values might happen to have the same | |
| absolute ordering regardless of the behavioral inconsistency. See | |
| <a class="xref" href="locale.html" title="24.1. Locale Support">Section 24.1</a> and <a class="xref" href="collation.html" title="24.2. Collation Support">Section 24.2</a> for | |
| further details about how <span class="productname">PostgreSQL</span> uses | |
| operating system locales and collations. | |
| </p></li><li class="listitem"><p> | |
| Structural inconsistencies between indexes and the heap relations | |
| that are indexed (when <em class="parameter"><code>heapallindexed</code></em> | |
| verification is performed). | |
| </p><p> | |
| There is no cross-checking of indexes against their heap relation | |
| during normal operation. Symptoms of heap corruption can be subtle. | |
| </p></li><li class="listitem"><p> | |
| Corruption caused by hypothetical undiscovered bugs in the | |
| underlying <span class="productname">PostgreSQL</span> access method | |
| code, sort code, or transaction management code. | |
| </p><p> | |
| Automatic verification of the structural integrity of indexes | |
| plays a role in the general testing of new or proposed | |
| <span class="productname">PostgreSQL</span> features that could plausibly allow a | |
| logical inconsistency to be introduced. Verification of table | |
| structure and associated visibility and transaction status | |
| information plays a similar role. One obvious testing strategy | |
| is to call <code class="filename">amcheck</code> functions continuously | |
| when running the standard regression tests. See <a class="xref" href="regress-run.html" title="33.1. Running the Tests">Section 33.1</a> for details on running the tests. | |
| </p></li><li class="listitem"><p> | |
| File system or storage subsystem faults where checksums happen to | |
| simply not be enabled. | |
| </p><p> | |
| Note that <code class="filename">amcheck</code> examines a page as represented in some | |
| shared memory buffer at the time of verification if there is only a | |
| shared buffer hit when accessing the block. Consequently, | |
| <code class="filename">amcheck</code> does not necessarily examine data read from the | |
| file system at the time of verification. Note that when checksums are | |
| enabled, <code class="filename">amcheck</code> may raise an error due to a checksum | |
| failure when a corrupt block is read into a buffer. | |
| </p></li><li class="listitem"><p> | |
| Corruption caused by faulty RAM, or the broader memory subsystem. | |
| </p><p> | |
| <span class="productname">PostgreSQL</span> does not protect against correctable | |
| memory errors and it is assumed you will operate using RAM that | |
| uses industry standard Error Correcting Codes (ECC) or better | |
| protection. However, ECC memory is typically only immune to | |
| single-bit errors, and should not be assumed to provide | |
| <span class="emphasis"><em>absolute</em></span> protection against failures that | |
| result in memory corruption. | |
| </p><p> | |
| When <em class="parameter"><code>heapallindexed</code></em> verification is | |
| performed, there is generally a greatly increased chance of | |
| detecting single-bit errors, since strict binary equality is | |
| tested, and the indexed attributes within the heap are tested. | |
| </p></li></ul></div><p> | |
| </p><p> | |
| Structural corruption can happen due to faulty storage hardware, or | |
| relation files being overwritten or modified by unrelated software. | |
| This kind of corruption can also be detected with | |
| <a class="link" href="checksums.html" title="30.2. Data Checksums"><span class="application">data page | |
| checksums</span></a>. | |
| </p><p> | |
| Relation pages which are correctly formatted, internally consistent, and | |
| correct relative to their own internal checksums may still contain | |
| logical corruption. As such, this kind of corruption cannot be detected | |
| with <span class="application">checksums</span>. Examples include toasted | |
| values in the main table which lack a corresponding entry in the toast | |
| table, and tuples in the main table with a Transaction ID that is older | |
| than the oldest valid Transaction ID in the database or cluster. | |
| </p><p> | |
| Multiple causes of logical corruption have been observed in production | |
| systems, including bugs in the <span class="productname">PostgreSQL</span> | |
| server software, faulty and ill-conceived backup and restore tools, and | |
| user error. | |
| </p><p> | |
| Corrupt relations are most concerning in live production environments, | |
| precisely the same environments where high risk activities are least | |
| welcome. For this reason, <code class="function">verify_heapam</code> has been | |
| designed to diagnose corruption without undue risk. It cannot guard | |
| against all causes of backend crashes, as even executing the calling | |
| query could be unsafe on a badly corrupted system. Access to <a class="link" href="catalogs-overview.html" title="53.1. Overview">catalog tables</a> is performed and could | |
| be problematic if the catalogs themselves are corrupted. | |
| </p><p> | |
| In general, <code class="filename">amcheck</code> can only prove the presence of | |
| corruption; it cannot prove its absence. | |
| </p></div><div class="sect2" id="AMCHECK-REPAIRING-CORRUPTION"><div class="titlepage"><div><div><h3 class="title">F.2.4. Repairing Corruption <a href="#AMCHECK-REPAIRING-CORRUPTION" class="id_link">#</a></h3></div></div></div><p> | |
| No error concerning corruption raised by <code class="filename">amcheck</code> should | |
| ever be a false positive. <code class="filename">amcheck</code> raises | |
| errors in the event of conditions that, by definition, should never | |
| happen, and so careful analysis of <code class="filename">amcheck</code> | |
| errors is often required. | |
| </p><p> | |
| There is no general method of repairing problems that | |
| <code class="filename">amcheck</code> detects. An explanation for the root cause of | |
| an invariant violation should be sought. <a class="xref" href="pageinspect.html" title="F.25. pageinspect — low-level inspection of database pages">pageinspect</a> may play a useful role in diagnosing | |
| corruption that <code class="filename">amcheck</code> detects. A <code class="command">REINDEX</code> | |
| may not be effective in repairing corruption. | |
| </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="adminpack.html" title="F.1. adminpack — pgAdmin support toolpack">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="contrib.html" title="Appendix F. Additional Supplied Modules and Extensions">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="auth-delay.html" title="F.3. auth_delay — pause on authentication failure">Next</a></td></tr><tr><td width="40%" align="left" valign="top">F.1. adminpack — pgAdmin support toolpack </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 16.3 Documentation">Home</a></td><td width="40%" align="right" valign="top"> F.3. auth_delay — pause on authentication failure</td></tr></table></div></body></html> |