Tim Starling has uploaded a new change for review.
https://gerrit.wikimedia.org/r/53483
Change subject: Reduce disruption during updateCollation.php
......................................................................
Reduce disruption during updateCollation.php
Have updateCollation.php order by cl_to, so that each category is
updated all at once. This minimises the time during which a category
will appear to be incorrectly sorted, while the maintenance script is in
progress.
Mark the cl_collation index as needing deletion, it was always pretty
pointless. You can't do much better than a full table scan when you're
changing the collation value on a wiki.
Increase the batch size since the lack of a cl_to,cl_from index means
that it will have to filesort each category. A larger batch size means
less sorts. As noted by Liangent on bug 45970, you can't order by
cl_sortkey since that will change during execution.
Also fix an inappropriate use of $wgMiserMode and remove a no-op from
the SET clause of the UPDATE.
Very lightly tested.
Also cherry-picked I803f20bc
Change-Id: I0a58ab79e7f982f4f289ccc2bd231f8b3ed6b217
---
M maintenance/tables.sql
M maintenance/updateCollation.php
2 files changed, 45 insertions(+), 20 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/core
refs/changes/83/53483/1
diff --git a/maintenance/tables.sql b/maintenance/tables.sql
index e501d35..6f567c9 100644
--- a/maintenance/tables.sql
+++ b/maintenance/tables.sql
@@ -560,10 +560,10 @@
-- callers won't be using an index: fix this?
CREATE INDEX /*i*/cl_sortkey ON /*_*/categorylinks
(cl_to,cl_type,cl_sortkey,cl_from);
--- Not really used?
+-- Used by the API (and some extensions)
CREATE INDEX /*i*/cl_timestamp ON /*_*/categorylinks (cl_to,cl_timestamp);
--- For finding rows with outdated collation
+-- FIXME: Not used, delete this
CREATE INDEX /*i*/cl_collation ON /*_*/categorylinks (cl_collation);
--
diff --git a/maintenance/updateCollation.php b/maintenance/updateCollation.php
index 04a2d47..0e2791c 100644
--- a/maintenance/updateCollation.php
+++ b/maintenance/updateCollation.php
@@ -35,7 +35,7 @@
* @ingroup Maintenance
*/
class UpdateCollation extends Maintenance {
- const BATCH_SIZE = 50; // Number of rows to process in one batch
+ const BATCH_SIZE = 10000; // Number of rows to process in one batch
const SYNC_INTERVAL = 20; // Wait for slaves after this many batches
public $sizeHistogram = array();
@@ -82,10 +82,13 @@
$collation = Collation::singleton();
}
- $options = array( 'LIMIT' => self::BATCH_SIZE, 'STRAIGHT_JOIN'
);
+ $options = array(
+ 'LIMIT' => self::BATCH_SIZE,
+ 'ORDER BY' => 'cl_to, cl_type, cl_from',
+ 'STRAIGHT_JOIN',
+ );
if ( $force || $dryRun ) {
- $options['ORDER BY'] = 'cl_from, cl_to';
$collationConds = array();
} else {
if ( $this->hasOption( 'previous-collation' ) ) {
@@ -96,17 +99,17 @@
);
}
- if ( !$wgMiserMode ) {
+ $count = $dbw->estimateRowCount(
+ 'categorylinks',
+ '*',
+ $collationConds,
+ __METHOD__
+ );
+ // Improve estimate if feasible
+ if ( $count < 1000000 ) {
$count = $dbw->selectField(
'categorylinks',
'COUNT(*)',
- $collationConds,
- __METHOD__
- );
- } else {
- $count = $dbw->estimateRowCount(
- 'categorylinks',
- '*',
$collationConds,
__METHOD__
);
@@ -126,7 +129,7 @@
$res = $dbw->select(
array( 'categorylinks', 'page' ),
array( 'cl_from', 'cl_to', 'cl_sortkey_prefix',
'cl_collation',
- 'cl_sortkey', 'page_namespace',
'page_title'
+ 'cl_sortkey', 'cl_type',
'page_namespace', 'page_title'
),
array_merge( $collationConds, $batchConds,
array( 'cl_from = page_id' ) ),
__METHOD__,
@@ -186,12 +189,8 @@
$dbw->commit( __METHOD__ );
}
- if ( ( $force || $dryRun ) && $row ) {
- $encFrom = $dbw->addQuotes( $row->cl_from );
- $encTo = $dbw->addQuotes( $row->cl_to );
- $batchConds = array(
- "(cl_from = $encFrom AND cl_to >
$encTo) " .
- " OR cl_from > $encFrom" );
+ if ( $row ) {
+ $batchConds = array( $this->getBatchCondition(
$row ) );
}
$count += $res->numRows();
@@ -212,6 +211,32 @@
}
}
+ /**
+ * Return an SQL expression selecting rows which sort above the given
row,
+ * assuming an ordering of cl_to, cl_type, cl_from
+ */
+ function getBatchCondition( $row ) {
+ $dbw = $this->getDB( DB_MASTER );
+ $fields = array( 'cl_to', 'cl_type', 'cl_from' );
+ $first = true;
+ $cond = false;
+ $prefix = false;
+ foreach ( $fields as $field ) {
+ $encValue = $dbw->addQuotes( $row->$field );
+ $inequality = "$field > $encValue";
+ $equality = "$field = $encValue";
+ if ( $first ) {
+ $cond = $inequality;
+ $prefix = $equality;
+ $first = false;
+ } else {
+ $cond .= " OR ($prefix AND $inequality)";
+ $prefix .= " AND $equality";
+ }
+ }
+ return $cond;
+ }
+
function updateSortKeySizeHistogram( $key ) {
$length = strlen( $key );
if ( !isset( $this->sizeHistogram[$length] ) ) {
--
To view, visit https://gerrit.wikimedia.org/r/53483
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I0a58ab79e7f982f4f289ccc2bd231f8b3ed6b217
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/core
Gerrit-Branch: wmf/1.21wmf11
Gerrit-Owner: Tim Starling <tstarl...@wikimedia.org>
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