{"id":1743,"date":"2009-10-21T17:36:30","date_gmt":"2009-10-21T07:36:30","guid":{"rendered":"http:\/\/www.flamingspork.com\/blog\/?p=1743"},"modified":"2009-10-21T17:36:30","modified_gmt":"2009-10-21T07:36:30","slug":"first-flesh-wound-in-create_tmp_table","status":"publish","type":"post","link":"https:\/\/www.flamingspork.com\/blog\/2009\/10\/21\/first-flesh-wound-in-create_tmp_table\/","title":{"rendered":"First flesh wound in create_tmp_table()"},"content":{"rendered":"<p>If you have needed a good reason to drink heavily and forget, may I suggest taking a look at create_tmp_table() and those who call it. It&#8217;s probably one of the best illustrations of rot and awful, incomprehensible APIs in the server (Drizzle inherited it from MySQL).<\/p>\n<p>In the normal paths for CREATE TABLE, you construct a data structure describing the table you want, create it and then open it. Opening a table gives you objects you can use to access it.<\/p>\n<p>create_tmp_table() instead constructs these objects directly and then does some direct calls into specific storage engines (ever wondered why you can&#8217;t use your own storage engine for temporary tables created during query execution? this is why). So instead of having one place to construct TableShare and Table, we have create_tmp_table() doing its own thing.<\/p>\n<p>I struck a blow against it today. Using the standard interfaces to create and open a table, I got the temporary tables created for INFORMATION_SCHEMA tables to use them and not create_tmp_table().<\/p>\n<p>When I finish converting the other 3 or 4 places that use create_tmp_table, I&#8217;ll be able to cut out at least 700 odd lines of code, cut out the horrible special case in the HEAP engine for &#8220;create table on open() even if create() was never called&#8221; and have an easy time making the transition to fully using the table proto as the specification for table structure.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>If you have needed a good reason to drink heavily and forget, may I suggest taking a look at create_tmp_table() and those who call it. It&#8217;s probably one of the best illustrations of rot and awful, incomprehensible APIs in the &hellip; <a href=\"https:\/\/www.flamingspork.com\/blog\/2009\/10\/21\/first-flesh-wound-in-create_tmp_table\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[75,14],"tags":[],"class_list":["post-1743","post","type-post","status-publish","format-standard","hentry","category-drizzle-work-et-al","category-mysql"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p5a6n8-s7","jetpack-related-posts":[{"id":1813,"url":"https:\/\/www.flamingspork.com\/blog\/2010\/03\/12\/writing-a-storage-engine-for-drizzle-part-2-create-table\/","url_meta":{"origin":1743,"position":0},"title":"Writing A Storage Engine for Drizzle, Part 2: CREATE TABLE","author":"Stewart Smith","date":"2010-03-12","format":false,"excerpt":"The DDL code paths for Drizzle are increasingly different from MySQL. For example, the embedded_innodb StorageEngine CREATE TABLE code path is completely different than what it would have to be for MySQL. This is because of a number of reasons, the primary one being that Drizzle uses a protobuf message\u2026","rel":"","context":"In &quot;drizzle&quot;","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1879,"url":"https:\/\/www.flamingspork.com\/blog\/2010\/05\/24\/using-the-row-buffer-in-drizzle-and-mysql\/","url_meta":{"origin":1743,"position":1},"title":"Using the row buffer in Drizzle (and MySQL)","author":"Stewart Smith","date":"2010-05-24","format":false,"excerpt":"Here's another bit of the API you may need to use in your storage engine (it also seems to be a rather unknown. I believe the only place where this has really been documented is ha_ndbcluster.cc, so here goes.... Drizzle (through inheritance from MySQL) has its own (in memory) row\u2026","rel":"","context":"In &quot;drizzle&quot;","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.flamingspork.com\/blog\/wp-content\/uploads\/2010\/04\/row-300x85.png?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":1650,"url":"https:\/\/www.flamingspork.com\/blog\/2009\/05\/27\/pluggable-metadata-stores-or-the-revenge-of-table-discovery\/","url_meta":{"origin":1743,"position":2},"title":"Pluggable Metadata stores (or&#8230; the revenge of table discovery)","author":"Stewart Smith","date":"2009-05-27","format":false,"excerpt":"Users of the ARCHIVE or NDB storage engines in MySQL may be aware of a MySQL feature known as \"table discovery\". For ARCHIVE, you can copy the archive data file around between servers and it magically works (you don't need to copy the FRM). For MySQL Cluster (NDB) it works\u2026","rel":"","context":"In &quot;drizzle&quot;","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":3234,"url":"https:\/\/www.flamingspork.com\/blog\/2013\/04\/04\/refactoring-internal-temporary-tables-another-stab-at-it\/","url_meta":{"origin":1743,"position":3},"title":"Refactoring Internal temporary tables (another stab at it)","author":"Stewart Smith","date":"2013-04-04","format":false,"excerpt":"A few weekends ago, I started to again look at the code in Drizzle for producing internal temporary tables. Basically, we have a few type of tables: Standard Temporary (from CREATE TEMPORARY TABLE) Temporary (from ALTER TABLE) Internal temporary (to help with query execution) If you're lucky enough to be\u2026","rel":"","context":"In &quot;code&quot;","block_context":{"text":"code","link":"https:\/\/www.flamingspork.com\/blog\/category\/code\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1745,"url":"https:\/\/www.flamingspork.com\/blog\/2009\/12\/09\/drizzle-frm-replacement-the-table-proto\/","url_meta":{"origin":1743,"position":4},"title":"Drizzle FRM replacement: the table proto","author":"Stewart Smith","date":"2009-12-09","format":false,"excerpt":"Drizzle originally inherited the FRM file from MySQL (which inherited it from UNIREG). The FRM file stores metadata about a table; what columns it has, what type those columns are, what indexes, any default values, comments etc are all stored in the FRM. In the days of MyISAM, this worked\u2026","rel":"","context":"In &quot;drizzle&quot;","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":1903,"url":"https:\/\/www.flamingspork.com\/blog\/2010\/04\/21\/storage-engine-api-write_row-create-select-and-ddl\/","url_meta":{"origin":1743,"position":5},"title":"Storage Engine API: write_row, CREATE SELECT and DDL","author":"Stewart Smith","date":"2010-04-21","format":false,"excerpt":"(this probably applies exactly the same for MySQL and Drizzle... but I'm just speaking about current Drizzle here) In my current merge request for the embedded-innodb\u00ef\u00bb\u00bf-create-select-transaction-arrgh branch (also see this specific revision), you'll notice an odd hoop that we have to jump through to make CREATE SELECT statements work with\u2026","rel":"","context":"In &quot;drizzle&quot;","block_context":{"text":"drizzle","link":"https:\/\/www.flamingspork.com\/blog\/category\/work-et-al\/drizzle-work-et-al\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts\/1743","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/comments?post=1743"}],"version-history":[{"count":1,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts\/1743\/revisions"}],"predecessor-version":[{"id":1744,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/posts\/1743\/revisions\/1744"}],"wp:attachment":[{"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/media?parent=1743"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/categories?post=1743"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.flamingspork.com\/blog\/wp-json\/wp\/v2\/tags?post=1743"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}