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Diffstat (limited to 'www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DIHandlers/DIBlobHandler.php')
| -rw-r--r-- | www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DIHandlers/DIBlobHandler.php | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DIHandlers/DIBlobHandler.php b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DIHandlers/DIBlobHandler.php new file mode 100644 index 00000000..f88ed878 --- /dev/null +++ b/www/wiki/extensions/SemanticMediaWiki/src/SQLStore/EntityStore/DIHandlers/DIBlobHandler.php @@ -0,0 +1,252 @@ +<?php + +namespace SMW\SQLStore\EntityStore\DIHandlers; + +use SMW\SQLStore\EntityStore\DataItemHandler; +use SMW\SQLStore\EntityStore\Exception\DataItemHandlerException; +use SMW\SQLStore\TableBuilder\FieldType; +use SMWDataItem as DataItem; +use SMWDIBlob as DIBlob; + +/** + * This class implements Store access to blob (string) data items. + * + * @license GNU GPL v2+ + * @since 1.8 + * + * @author Nischay Nahata + */ +class DIBlobHandler extends DataItemHandler { + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getTableFields() { + return [ + 'o_blob' => FieldType::TYPE_BLOB, + 'o_hash' => $this->getCharFieldType() + ]; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getFetchFields() { + return [ + 'o_blob' => FieldType::TYPE_BLOB, + 'o_hash' => $this->getCharFieldType() + ]; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getTableIndexes() { + return [ + + 's_id,o_hash', + + // pvalue select + // SELECT p_id,o_hash FROM `smw_di_blob` WHERE p_id = '310174' AND ( o_hash LIKE '%test%' ) LIMIT 11 + 'p_id,o_hash', + ]; + } + + /** + * @since 3.0 + * + * {@inheritDoc} + */ + public function getIndexHint( $key ) { + + // Store::getPropertySubjects has seen to choose the wrong index + + // SELECT smw_id, smw_title, smw_namespace, smw_iw, smw_subobject, smw_sortkey, smw_sort + // FROM `smw_object_ids` + // INNER JOIN `smw_di_blob` AS t1 FORCE INDEX(s_id) ON t1.s_id=smw_id + // WHERE t1.p_id='310174' AND smw_iw!=':smw' + // AND smw_iw!=':smw-delete' AND smw_iw!=':smw-redi' + // GROUP BY smw_sort, smw_id LIMIT 26 + // + // 137.4161ms SMWSQLStore3Readers::getPropertySubjects + // + // vs. + // + // SELECT smw_id, smw_title, smw_namespace, smw_iw, smw_subobject, smw_sortkey, smw_sort + // FROM `smw_object_ids` + // INNER JOIN `smw_di_blob` AS t1 ON t1.s_id=smw_id + // WHERE t1.p_id='310174' AND smw_iw!=':smw' AND smw_iw!=':smw-delete' + // AND smw_iw!=':smw-redi' + // GROUP BY smw_sort, smw_id LIMIT 26 + // + // 23482.1451ms SMWSQLStore3Readers::getPropertySubjects + if ( 'property.subjects' && $this->isDbType( 'mysql' ) ) { + return 's_id'; + } + + return ''; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getWhereConds( DataItem $dataItem ) { + + $isKeyword = $dataItem->getOption( 'is.keyword' ); + $text = $dataItem->getString(); + + return [ + 'o_hash' => $isKeyword ? $dataItem->normalize( $text ) : $this->makeHash( $text ) + ]; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getInsertValues( DataItem $dataItem ) { + + $isKeyword = $dataItem->getOption( 'is.keyword' ); + + $text = htmlspecialchars_decode( trim( $dataItem->getString() ), ENT_QUOTES ); + $hash = $isKeyword ? $dataItem->normalize( $text ) : $this->makeHash( $text ); + + if ( $this->isDbType( 'postgres' ) ) { + $text = pg_escape_bytea( $text ); + } + + if ( mb_strlen( $text ) <= $this->getMaxLength() && !$isKeyword ) { + $text = null; + } + + return [ + 'o_blob' => $text, + 'o_hash' => $hash, + ]; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getIndexField() { + return 'o_hash'; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function getLabelField() { + return 'o_hash'; + } + + /** + * @since 1.8 + * + * {@inheritDoc} + */ + public function dataItemFromDBKeys( $dbkeys ) { + + if ( !is_array( $dbkeys ) || count( $dbkeys ) != 2 ) { + throw new DataItemHandlerException( 'Failed to create data item from DB keys.' ); + } + + if ( $this->isDbType( 'postgres' ) ) { + $dbkeys[0] = pg_unescape_bytea( $dbkeys[0] ); + } + + // empty blob: use "hash" string + if ( $dbkeys[0] == '' ) { + return new DIBlob( $dbkeys[1] ); + } + + return new DIBlob( $dbkeys[0] ); + } + + /** + * Method to make a hashed representation for strings of length greater + * than DIBlobHandler::getMaxLength to be used for selecting and sorting. + * + * @since 1.8 + * @param $string string + * + * @return string + */ + private function makeHash( $string ) { + + $length = $this->getMaxLength(); + + if( mb_strlen( $string ) <= $length ) { + return $string; + } + + return mb_substr( $string, 0, $length - 32 ) . md5( $string ); + } + + /** + * Maximal number of bytes (chars) to be stored in the hash field of + * the table. Must not be bigger than 255 (the length of our VARCHAR + * field in the DB). Strings that are longer than this will be stored + * as a blob, and the hash will only start with the original string + * but the last 32 bytes are used for a hash. So the minimal portion + * of the string that is stored literally in the hash is 32 chars + * less. + * + * The value of 72 was chosen since it leads to a smaller index size + * at the cost of needing more blobs in cases where many strings are + * of length 73 to 255. But keeping the index small seems more + * important than saving disk space. Also, with 72 bytes there are at + * least 40 bytes of content available for sorting and prefix matching, + * which should be more than enough in most contexts. + * + * @since 1.8 + * + * Using `SMW_FIELDT_CHAR_LONG` as option in `smwgFieldTypeFeatures` + * will extend the field size to 300 and expands the maximum matchable + * string length to 300-32 for LIKE/NLIKE queries. + * + * @since 3.0 + */ + private function getMaxLength() { + + $length = 72; + + if ( $this->isEnabledFeature( SMW_FIELDT_CHAR_LONG ) ) { + $length = FieldType::CHAR_LONG_LENGTH; + } + + return $length; + } + + private function getCharFieldType() { + + $fieldType = FieldType::FIELD_TITLE; + + if ( $this->isEnabledFeature( SMW_FIELDT_CHAR_NOCASE ) ) { + $fieldType = FieldType::TYPE_CHAR_NOCASE; + } + + if ( $this->isEnabledFeature( SMW_FIELDT_CHAR_LONG ) ) { + $fieldType = FieldType::TYPE_CHAR_LONG; + } + + if ( $this->isEnabledFeature( SMW_FIELDT_CHAR_LONG ) && $this->isEnabledFeature( SMW_FIELDT_CHAR_NOCASE ) ) { + $fieldType = FieldType::TYPE_CHAR_LONG_NOCASE; + } + + return $fieldType; + } + +} |