diff options
| -rw-r--r-- | odb/pgsql/connection.cxx | 6 | ||||
| -rw-r--r-- | odb/pgsql/connection.hxx | 6 | ||||
| -rw-r--r-- | odb/pgsql/database.cxx | 127 |
3 files changed, 115 insertions, 24 deletions
diff --git a/odb/pgsql/connection.cxx b/odb/pgsql/connection.cxx index 1939e23..01399c9 100644 --- a/odb/pgsql/connection.cxx +++ b/odb/pgsql/connection.cxx @@ -77,6 +77,12 @@ namespace odb clear_prepared_map (); } + int connection:: + server_version () const + { + return PQserverVersion (handle_); + } + transaction_impl* connection:: begin () { diff --git a/odb/pgsql/connection.hxx b/odb/pgsql/connection.hxx index 57837ee..316dfeb 100644 --- a/odb/pgsql/connection.hxx +++ b/odb/pgsql/connection.hxx @@ -115,6 +115,12 @@ namespace odb return handle_; } + // Server version as returned by PQserverVersion(), for example, 90200 + // (9.2.0), 90201 (9.2.1), 100000 (10.0), 110001 (11.1). + // + int + server_version () const; + statement_cache_type& statement_cache () { diff --git a/odb/pgsql/database.cxx b/odb/pgsql/database.cxx index 630150c..e7f3bd0 100644 --- a/odb/pgsql/database.cxx +++ b/odb/pgsql/database.cxx @@ -2,6 +2,7 @@ // copyright : Copyright (c) 2009-2017 Code Synthesis Tools CC // license : GNU GPL v2; see accompanying LICENSE file +#include <cstring> // strlen() #include <sstream> #include <odb/pgsql/traits.hxx> @@ -234,17 +235,17 @@ namespace odb { schema_version_info& svi (schema_version_map_[name]); + // Quoted table name. + // + const char* table ( + !svi.version_table.empty () ? svi.version_table.c_str () : + !schema_version_table_.empty () ? schema_version_table_.c_str () : + /* */ "\"schema_version\""); + // Construct the SELECT statement text. // string text ("SELECT \"version\", \"migration\" FROM "); - - if (!svi.version_table.empty ()) - text += svi.version_table; // Already quoted. - else if (!schema_version_table_.empty ()) - text += schema_version_table_; // Already quoted. - else - text += "\"schema_version\""; - + text += table; text += " WHERE \"name\" = $1"; // Bind parameters and results. @@ -284,11 +285,50 @@ namespace odb pgsql::connection& c ( cp != 0 ? *cp : transaction::current ().connection ()); - try + // If we are in the user's transaction then things are complicated. When + // we try to execute SELECT on a non-existent table, PG "poisons" the + // transaction (those "current transaction is aborted, commands ignored + // until end of transaction block" messages in the log). Which means all + // the user's schema creation statements that are likely to follow will + // fail. + // + // There doesn't seem to be a better way to solve this than to check for + // the table's existence. It is relatively easy to do with to_regclass() + // in 9.4+ and a real pain in earlier versions. So we are going to do + // this for 9.4+ and for older versions the workaround is to "pre-call" + // database::schema_version() outside of any transaction. + // + bool exists (true); + if (cp == 0 && c.server_version () >= 90400) { + size_t psize[1] = {strlen (table)}; + bool pnull[1] = {false}; + bind pbind[1] = {{bind::text, + const_cast<char*> (table), + &psize[0], + psize[0], + &pnull[0], + 0}}; + binding param (pbind, 1); + param.version++; + + unsigned int param_types[1] = {text_oid}; + + char* values[1]; + int lengths[1]; + int formats[1]; + native_binding nparam (values, lengths, formats, 1); + + bool rnull[1]; + bind rbind[1] = {{bind::boolean_, &exists, 0, 0, &rnull[1], 0}}; + binding result (rbind, 1); + result.version++; + + // Note that to_regclass() seems happy to accept a quoted table name. + // select_statement st (c, - "odb_database_schema_version", - text.c_str (), + "odb_database_schema_version_exists", + "SELECT to_regclass($1::cstring) IS NOT NULL", false, // Don't process. false, // Don't optimize. param_types, @@ -297,6 +337,7 @@ namespace odb nparam, result, false); + st.execute (); auto_result ar (st); @@ -304,16 +345,10 @@ namespace odb { case select_statement::success: { - value_traits<unsigned long long, id_bigint>::set_value ( - svi.version, version, rnull[0]); assert (st.fetch () == select_statement::no_data); break; } case select_statement::no_data: - { - svi.version = 0; // No schema. - break; - } case select_statement::truncated: { assert (false); @@ -321,14 +356,58 @@ namespace odb } } } - catch (const database_exception& e) + + // Assume no schema until determined otherwise. + // + svi.version = 0; + + if (exists) { - // Detect the case where there is no version table. - // - if (e.sqlstate () == "42P01") - svi.version = 0; // No schema. - else - throw; + try + { + select_statement st (c, + "odb_database_schema_version_query", + text.c_str (), + false, // Don't process. + false, // Don't optimize. + param_types, + 1, + param, + nparam, + result, + false); + st.execute (); + auto_result ar (st); + + switch (st.fetch ()) + { + case select_statement::success: + { + value_traits<unsigned long long, id_bigint>::set_value ( + svi.version, version, rnull[0]); + assert (st.fetch () == select_statement::no_data); + break; + } + case select_statement::no_data: + { + // No schema. + break; + } + case select_statement::truncated: + { + assert (false); + break; + } + } + } + catch (const database_exception& e) + { + // Detect the case where there is no version table (the implicit + // transaction case). + // + if (e.sqlstate () != "42P01") + throw; + } } return svi; |